@article{
 title = {Quantum rates in dissipative systems with spatially varying friction},
 type = {article},
 year = {2024},
 pages = {24110},
 volume = {161},
 websites = {/aip/jcp/article/161/2/024110/3302755/Quantum-rates-in-dissipative-systems-with,https://pubs.aip.org/jcp/article/161/2/024110/3302755/Quantum-rates-in-dissipative-systems-with,http://www.ncbi.nlm.nih.gov/pubmed/38984959},
 month = {7},
 publisher = {American Institute of Physics},
 day = {14},
 id = {5afca478-a049-3078-a5b1-82bbf79e4891},
 created = {2024-10-11T14:59:32.367Z},
 accessed = {2024-10-11},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.004Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {We investigate whether making the friction spatially dependent on the reaction coordinate introduces quantum effects into the thermal reaction rates for dissipative reactions. Quantum rates are calculated using the numerically exact multi-configuration time-dependent Hartree method, as well as the approximate ring-polymer molecular dynamics (RPMD), ring-polymer instanton methods, and classical molecular dynamics. By conducting simulations across a wide range of temperatures and friction strengths, we can identify the various regimes that govern the reactive dynamics. At high temperatures, in addition to the spatial-diffusion and energy-diffusion regimes predicted by Kramer’s rate theory, a (coherent) tunneling-dominated regime is identified at low friction. At low temperatures, incoherent tunneling dominates most of Kramer’s curve, except at very low friction, when coherent tunneling becomes dominant. Unlike in classical mechanics, the bath’s influence changes the equilibrium time-independent properties of the system, leading to a complex interplay between spatially dependent friction and nuclear quantum effects even at high temperatures. More specifically, a realistic friction profile can lead to an increase (or decrease) of the quantum (classical) rates with friction within the spatial-diffusion regime, showing that classical and quantum rates display qualitatively different behaviors. Except at very low frictions, we find that RPMD captures most of the quantum effects in the thermal reaction rates.},
 bibtype = {article},
 author = {Bridge, Oliver and Lazzaroni, Paolo and Martinazzo, Rocco and Rossi, Mariana and Althorpe, Stuart C. and Litman, Yair},
 doi = {10.1063/5.0216823},
 journal = {The Journal of Chemical Physics},
 number = {2}
}

We investigate whether making the friction spatially dependent on the reaction coordinate introduces quantum effects into the thermal reaction rates for dissipative reactions. Quantum rates are calculated using the numerically exact multi-configuration time-dependent Hartree method, as well as the approximate ring-polymer molecular dynamics (RPMD), ring-polymer instanton methods, and classical molecular dynamics. By conducting simulations across a wide range of temperatures and friction strengths, we can identify the various regimes that govern the reactive dynamics. At high temperatures, in addition to the spatial-diffusion and energy-diffusion regimes predicted by Kramer’s rate theory, a (coherent) tunneling-dominated regime is identified at low friction. At low temperatures, incoherent tunneling dominates most of Kramer’s curve, except at very low friction, when coherent tunneling becomes dominant. Unlike in classical mechanics, the bath’s influence changes the equilibrium time-independent properties of the system, leading to a complex interplay between spatially dependent friction and nuclear quantum effects even at high temperatures. More specifically, a realistic friction profile can lead to an increase (or decrease) of the quantum (classical) rates with friction within the spatial-diffusion regime, showing that classical and quantum rates display qualitatively different behaviors. Except at very low frictions, we find that RPMD captures most of the quantum effects in the thermal reaction rates.

@article{
 title = {Dynamics of the molecular geometric phase},
 type = {article},
 year = {2024},
 pages = {243002},
 volume = {132},
 websites = {https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.243002,https://link.aps.org/doi/10.1103/PhysRevLett.132.243002,http://arxiv.org/abs/2312.02823},
 month = {12},
 publisher = {American Physical Society},
 day = {5},
 id = {4d124688-b050-31bf-8014-6dbe61379805},
 created = {2024-10-11T14:59:57.349Z},
 accessed = {2024-10-11},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-19T12:03:17.766Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The fate of the molecular geometric phase in an exact dynamical framework is investigated with the help of the exact factorization of the wavefunction and a recently proposed quantum hydrodynamical description of its dynamics. An instantaneous, gauge invariant phase is introduced for arbitrary paths in nuclear configuration space in terms of hydrodynamical variables, and shown to reduce to the adiabatic geometric phase when the state is adiabatic and the path is closed. The evolution of the closed-path phase over time is shown to adhere to a Maxwell-Faraday induction law, with non-conservative forces arising from the electron dynamics that play the role of electromotive forces. We identify the pivotal forces that are able to change the value of the phase, thereby challenging any topological argument. Nonetheless, negligible changes in the phase occur when the local dynamics along the probe loop is approximately adiabatic. In other words, the adiabatic idealization of geometric phase effects may remain suitable for effectively describing certain dynamic observables.},
 bibtype = {article},
 author = {Martinazzo, Rocco and Burghardt, Irene},
 doi = {10.1103/PhysRevLett.132.243002},
 journal = {Physical Review Letters},
 number = {24}
}

The fate of the molecular geometric phase in an exact dynamical framework is investigated with the help of the exact factorization of the wavefunction and a recently proposed quantum hydrodynamical description of its dynamics. An instantaneous, gauge invariant phase is introduced for arbitrary paths in nuclear configuration space in terms of hydrodynamical variables, and shown to reduce to the adiabatic geometric phase when the state is adiabatic and the path is closed. The evolution of the closed-path phase over time is shown to adhere to a Maxwell-Faraday induction law, with non-conservative forces arising from the electron dynamics that play the role of electromotive forces. We identify the pivotal forces that are able to change the value of the phase, thereby challenging any topological argument. Nonetheless, negligible changes in the phase occur when the local dynamics along the probe loop is approximately adiabatic. In other words, the adiabatic idealization of geometric phase effects may remain suitable for effectively describing certain dynamic observables.

@article{
 title = {Emergence of the Molecular Geometric Phase from Exact Electron–Nuclear Dynamics},
 type = {article},
 year = {2024},
 pages = {10416-10424},
 volume = {15},
 websites = {https://pubs.acs.org/doi/full/10.1021/acs.jpclett.4c02035},
 month = {10},
 publisher = {American Chemical Society},
 day = {17},
 id = {67bb9a2d-3092-310f-b565-eeaafc1f0b17},
 created = {2024-10-19T11:59:39.217Z},
 accessed = {2024-10-19},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-19T12:00:29.464Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Geometric phases play a crucial role in diverse fields. In molecules, they appear when a reaction path encircles an intersection between adiabatic potential energy surfaces and the molecular wave f...},
 bibtype = {article},
 author = {Martinazzo, Rocco and Burghardt, Irene},
 doi = {10.1021/ACS.JPCLETT.4C02035},
 journal = {The Journal of Physical Chemistry Letters},
 number = {41}
}

Geometric phases play a crucial role in diverse fields. In molecules, they appear when a reaction path encircles an intersection between adiabatic potential energy surfaces and the molecular wave f...

@article{
 title = {Quantum algorithms for grid-based variational time evolution},
 type = {article},
 year = {2023},
 pages = {1139},
 volume = {7},
 websites = {https://arxiv.org/abs/2203.02521v1,https://quantum-journal.org/papers/q-2023-10-12-1139/},
 month = {10},
 day = {12},
 id = {327c158d-698e-3722-91a6-debb0a593fbd},
 created = {2022-06-07T10:44:32.918Z},
 accessed = {2022-06-07},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.225Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The simulation of quantum dynamics calls for quantum algorithms working in first quantized grid encodings. Here, we propose a variational quantum algorithm for performing quantum dynamics in first quantization. In addition to the usual reduction in circuit depth conferred by variational approaches, this algorithm also enjoys several advantages compared to previously proposed ones. For instance, variational approaches suffer from the need for a large number of measurements. However, the grid encoding of first quantized Hamiltonians only requires measuring in position and momentum bases, irrespective of the system size. Their combination with variational approaches is therefore particularly attractive. Moreover, heuristic variational forms can be employed to overcome the limitation of the hard decomposition of Trotterized first quantized Hamiltonians into quantum gates. We apply this quantum algorithm to the dynamics of several systems in one and two dimensions. Our simulations exhibit the previously observed numerical instabilities of variational time propagation approaches. We show how they can be significantly attenuated through subspace diagonalization at a cost of an additional O ( M N 2 ) 2-qubit gates where M is the number of dimensions and N M is the total number of grid points.},
 bibtype = {article},
 author = {Ollitrault, Pauline J and Jandura, Sven and Miessen, Alexander and Burghardt, Irene and Martinazzo, Rocco and Tacchino, Francesco and Tavernelli, Ivano},
 doi = {10.22331/q-2023-10-12-1139},
 journal = {Quantum}
}

The simulation of quantum dynamics calls for quantum algorithms working in first quantized grid encodings. Here, we propose a variational quantum algorithm for performing quantum dynamics in first quantization. In addition to the usual reduction in circuit depth conferred by variational approaches, this algorithm also enjoys several advantages compared to previously proposed ones. For instance, variational approaches suffer from the need for a large number of measurements. However, the grid encoding of first quantized Hamiltonians only requires measuring in position and momentum bases, irrespective of the system size. Their combination with variational approaches is therefore particularly attractive. Moreover, heuristic variational forms can be employed to overcome the limitation of the hard decomposition of Trotterized first quantized Hamiltonians into quantum gates. We apply this quantum algorithm to the dynamics of several systems in one and two dimensions. Our simulations exhibit the previously observed numerical instabilities of variational time propagation approaches. We show how they can be significantly attenuated through subspace diagonalization at a cost of an additional O ( M N 2 ) 2-qubit gates where M is the number of dimensions and N M is the total number of grid points.

@article{
 title = {Bending the rules of PAH hydrogenation: the case of corannulene},
 type = {article},
 year = {2023},
 keywords = {ISM: molecules,astrochemistry,methods: laboratory: molecular,molecular processes},
 pages = {5567-5578},
 volume = {519},
 websites = {https://dx.doi.org/10.1093/mnras/stad054,https://academic.oup.com/mnras/article/519/4/5567/6987293},
 month = {1},
 publisher = {Oxford Academic},
 day = {17},
 id = {a45fcd9f-1d91-37c1-9e1d-6df583b5478e},
 created = {2024-10-11T14:51:44.477Z},
 accessed = {2024-10-11},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:17.909Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The interaction of a curved polycyclic aromatic hydrocarbon (PAH), corannulene (C20H10), with H-atoms leading to the formation of highly superhydrogenated species was studied. In particular, we determined the H-atom addition sequence to a monolayer of corannulene deposited on a graphite surface in order to understand the effect of curvature on the interaction of PAHs with H-atoms. We also investigated why superhydrogenated corannulene species with a certain number of additional H-atoms are more stable than the others. A combination of thermal desorption mass spectrometry measurements and density functional theory calculations was used to reveal and understand the presence of the most stable configurations in the superhydrogenation sequence of corannulene. Specifically, the experiments demonstrate the presence of stable configurations of superhydrogenated corannulene at specific hydrogenation levels of 2, 6, 8, 10, 12, 14, 16, 17, and 18 extra H-atoms. Density functional theory calculations of binding energies and barrier heights explain why some of these configurations are particularly stable and provide new insights into the superhydrogenation of curved PAH molecules under interstellar conditions.},
 bibtype = {article},
 author = {Leccese, Mirko and Jaganathan, R. and Slumstrup, L. and Thrower, J. D. and Hornekær, L. and Martinazzo, R.},
 doi = {10.1093/mnras/stad054},
 journal = {Monthly Notices of the Royal Astronomical Society},
 number = {4}
}

The interaction of a curved polycyclic aromatic hydrocarbon (PAH), corannulene (C20H10), with H-atoms leading to the formation of highly superhydrogenated species was studied. In particular, we determined the H-atom addition sequence to a monolayer of corannulene deposited on a graphite surface in order to understand the effect of curvature on the interaction of PAHs with H-atoms. We also investigated why superhydrogenated corannulene species with a certain number of additional H-atoms are more stable than the others. A combination of thermal desorption mass spectrometry measurements and density functional theory calculations was used to reveal and understand the presence of the most stable configurations in the superhydrogenation sequence of corannulene. Specifically, the experiments demonstrate the presence of stable configurations of superhydrogenated corannulene at specific hydrogenation levels of 2, 6, 8, 10, 12, 14, 16, 17, and 18 extra H-atoms. Density functional theory calculations of binding energies and barrier heights explain why some of these configurations are particularly stable and provide new insights into the superhydrogenation of curved PAH molecules under interstellar conditions.

@article{
 title = {Anomalous delocalization of resonant states in graphene & the vacancy magnetic moment},
 type = {article},
 year = {2023},
 keywords = {carbon atom vacancy,graphene,hybrid functionals,inverse participation ratio,local magnetic moment,resonant state,slab-supercell},
 pages = {024010},
 volume = {5},
 websites = {https://iopscience.iop.org/article/10.1088/2516-1075/acdbf4,https://iopscience.iop.org/article/10.1088/2516-1075/acdbf4/meta},
 month = {6},
 publisher = {IOP Publishing},
 day = {1},
 id = {828543e9-b573-36c4-8665-f3c544322082},
 created = {2024-10-11T14:56:26.625Z},
 accessed = {2024-10-11},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.021Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Carbon atom vacancies in graphene give rise to a local magnetic moment of σ + π origin, whose magnitude is yet uncertain and debated. Partial quenching of π magnetism has been ubiquitously reported in periodic first principles calculations, with magnetic moments scattered in the range 1.0–2.0 µ B , slowly converging to the lower or the upper end, depending on how the diluted limit is approached. By contrast, (ensemble) density functional theory calculations on cluster models neatly converge to the value of 2 μ B when increasing the system size. This stunning discrepancy has sparked a debate about the role of defect–defect interactions and self-doping, and about the importance of the self-interaction-error in the density-functional-theory description of the vacancy-induced states. Here, we settle this puzzle by showing that the problem has a fundamental, mono-electronic origin which is related to the special (periodic) arrangement of defects that results when using the slab-supercell approach. Specifically, we report the existence of resonant states that are anomalously delocalized over the lattice and that make the π midgap band unphysically dispersive, hence prone to self-doping and quenching of the π magnetism. Hybrid functionals fix the problem by widening the gap between the spin-resolved π midgap bands, without reducing their artificial widths. As a consequence, while reconciling the magnetic moment with expectations, they predict a spin-splitting which is one order of magnitude larger than found in experiments.},
 bibtype = {article},
 author = {Leccese, Mirko and Martinazzo, Rocco},
 doi = {10.1088/2516-1075/acdbf4},
 journal = {Electronic Structure},
 number = {2}
}

Carbon atom vacancies in graphene give rise to a local magnetic moment of σ + π origin, whose magnitude is yet uncertain and debated. Partial quenching of π magnetism has been ubiquitously reported in periodic first principles calculations, with magnetic moments scattered in the range 1.0–2.0 µ B , slowly converging to the lower or the upper end, depending on how the diluted limit is approached. By contrast, (ensemble) density functional theory calculations on cluster models neatly converge to the value of 2 μ B when increasing the system size. This stunning discrepancy has sparked a debate about the role of defect–defect interactions and self-doping, and about the importance of the self-interaction-error in the density-functional-theory description of the vacancy-induced states. Here, we settle this puzzle by showing that the problem has a fundamental, mono-electronic origin which is related to the special (periodic) arrangement of defects that results when using the slab-supercell approach. Specifically, we report the existence of resonant states that are anomalously delocalized over the lattice and that make the π midgap band unphysically dispersive, hence prone to self-doping and quenching of the π magnetism. Hybrid functionals fix the problem by widening the gap between the spin-resolved π midgap bands, without reducing their artificial widths. As a consequence, while reconciling the magnetic moment with expectations, they predict a spin-splitting which is one order of magnitude larger than found in experiments.

@article{
 title = {Quantum algorithms for grid-based variational time evolution},
 type = {article},
 year = {2023},
 pages = {1139},
 volume = {7},
 websites = {https://quantum-journal.org/papers/q-2023-10-12-1139/},
 month = {10},
 publisher = {Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften},
 day = {12},
 id = {bc30c1e8-e51c-35c2-bc91-f5fe892f5632},
 created = {2024-10-11T14:56:54.418Z},
 accessed = {2024-10-11},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.023Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The simulation of quantum dynamics calls for quantum algorithms working in first quantized grid encodings. Here, we propose a variational quantum algorithm for performing quantum dynamics in first quantization. In addition to the usual reduction in circuit depth conferred by variational approaches, this algorithm also enjoys several advantages compared to previously proposed ones. For instance, variational approaches suffer from the need for a large number of measurements. However, the grid encoding of first quantized Hamiltonians only requires measuring in position and momentum bases, irrespective of the system size. Their combination with variational approaches is therefore particularly attractive. Moreover, heuristic variational forms can be employed to overcome the limitation of the hard decomposition of Trotterized first quantized Hamiltonians into quantum gates. We apply this quantum algorithm to the dynamics of several systems in one and two dimensions. Our simulations exhibit the previously observed numerical instabilities of variational time propagation approaches. We show how they can be significantly attenuated through subspace diagonalization at a cost of an additional O ( M N 2 ) 2-qubit gates where M is the number of dimensions and N M is the total number of grid points.},
 bibtype = {article},
 author = {Ollitrault, Pauline J. and Jandura, Sven and Miessen, Alexander and Burghardt, Irene and Martinazzo, Rocco and Tacchino, Francesco and Tavernelli, Ivano},
 doi = {10.22331/q-2023-10-12-1139},
 journal = {Quantum}
}

The simulation of quantum dynamics calls for quantum algorithms working in first quantized grid encodings. Here, we propose a variational quantum algorithm for performing quantum dynamics in first quantization. In addition to the usual reduction in circuit depth conferred by variational approaches, this algorithm also enjoys several advantages compared to previously proposed ones. For instance, variational approaches suffer from the need for a large number of measurements. However, the grid encoding of first quantized Hamiltonians only requires measuring in position and momentum bases, irrespective of the system size. Their combination with variational approaches is therefore particularly attractive. Moreover, heuristic variational forms can be employed to overcome the limitation of the hard decomposition of Trotterized first quantized Hamiltonians into quantum gates. We apply this quantum algorithm to the dynamics of several systems in one and two dimensions. Our simulations exhibit the previously observed numerical instabilities of variational time propagation approaches. We show how they can be significantly attenuated through subspace diagonalization at a cost of an additional O ( M N 2 ) 2-qubit gates where M is the number of dimensions and N M is the total number of grid points.

@article{
 title = {Quantum hydrodynamics of coupled electron-nuclear systems},
 type = {article},
 year = {2023},
 websites = {http://arxiv.org/abs/2310.08766},
 month = {10},
 day = {12},
 id = {7700a1b4-907f-3488-90bd-01f619c30a15},
 created = {2024-10-11T14:57:09.073Z},
 accessed = {2024-10-11},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-11T15:04:23.856Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The quantum dynamics of electron-nuclear systems is analyzed from the perspective of the exact factorization of the wavefunction, with the aim of defining gauge invariant equations of motion for both the nuclei and the electrons. For pure states this is accomplished with a quantum hydrodynamical description of the nuclear dynamics and electronic density operators tied to the fluid elements. For statistical mixtures of states the exact factorization approach is extended to two limiting situations that we call "type-n" and "type-e" mixtures, depending on whether the nuclei or the electrons are, respectively, in an intrinsically mixed state. In both cases a fully gauge invariant formulation of the dynamics is obtained again in hydrodynamic form with the help of mechanical momentum moments (MMMs). Nuclear MMMs extend in a gauge invariant way the ordinary momentum moments of the Wigner distribution associated with a density matrix of positional variables, electron MMMs are operator-valued and represent a generalization of the (conditional) density operators used for pure states. The theory presented here bridges exact quantum dynamics with several mixed quantum-classical approaches currently in use to tackle non-adiabatic molecular problems, offering a foundation for systematic improvements. It further connects to non-adiabatic theories in condensed-phase systems. As an example, we re-derive the finite-temperature theory of electronic friction of Dou, Miao \& Subotnik (Phys. Rev. Lett. 119, 046001 (2017)) from the dynamics of "type-e" mixtures and discuss possible improvements.},
 bibtype = {article},
 author = {Martinazzo, Rocco and Burghardt, Irene}
}

The quantum dynamics of electron-nuclear systems is analyzed from the perspective of the exact factorization of the wavefunction, with the aim of defining gauge invariant equations of motion for both the nuclei and the electrons. For pure states this is accomplished with a quantum hydrodynamical description of the nuclear dynamics and electronic density operators tied to the fluid elements. For statistical mixtures of states the exact factorization approach is extended to two limiting situations that we call "type-n" and "type-e" mixtures, depending on whether the nuclei or the electrons are, respectively, in an intrinsically mixed state. In both cases a fully gauge invariant formulation of the dynamics is obtained again in hydrodynamic form with the help of mechanical momentum moments (MMMs). Nuclear MMMs extend in a gauge invariant way the ordinary momentum moments of the Wigner distribution associated with a density matrix of positional variables, electron MMMs are operator-valued and represent a generalization of the (conditional) density operators used for pure states. The theory presented here bridges exact quantum dynamics with several mixed quantum-classical approaches currently in use to tackle non-adiabatic molecular problems, offering a foundation for systematic improvements. It further connects to non-adiabatic theories in condensed-phase systems. As an example, we re-derive the finite-temperature theory of electronic friction of Dou, Miao \& Subotnik (Phys. Rev. Lett. 119, 046001 (2017)) from the dynamics of "type-e" mixtures and discuss possible improvements.

@article{
 title = {Quantum Dynamics with Electronic Friction},
 type = {article},
 year = {2022},
 pages = {206002},
 volume = {128},
 websites = {http://arxiv.org/abs/2108.02622,http://dx.doi.org/10.1103/PhysRevLett.128.206002,https://link.aps.org/doi/10.1103/PhysRevLett.128.206002},
 month = {5},
 day = {20},
 id = {1291ec58-c5a7-3ee2-aa7e-06c3aef23330},
 created = {2022-06-07T10:40:39.503Z},
 accessed = {2022-06-07},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.123Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {A theory of electronic friction is developed using the exact factorization of the electron-nuclear wavefunction. No assumption is made regarding the electronic bath, which can be made of independent or interacting electrons, and the nuclei are treated quantally. The ensuing equation of motion for the nuclear wavefunction is a non-linear Schr\"odinger equation including a friction term. The resulting friction kernel agrees with a previously derived mixed quantum-classical result by Dou, Miao \& Subotnik (\emphPhys. Rev. Lett. \textbf119, 046001 (2017)), except for a \emphpseudo-magnetic contribution in the latter that is here removed. More specifically, it is shown that the electron dynamics generally washes out the\emph gauge fields appearing in the adiabatic dynamics. However, at T=0 K, the \emphpseudo-magnetic force is fully re-established in the typical situation where the electrons respond rapidy on the slow time-scale of the nuclear dynamics (Markov limit). Hence, we predict Berry's phase effects to be observable also in the presence of electronic friction, and non-trivial geometric phases should be attainable for molecules on metallic magnetic surfaces.},
 bibtype = {article},
 author = {Martinazzo, Rocco and Burghardt, Irene},
 doi = {10.1103/PhysRevLett.128.206002},
 journal = {Physical Review Letters},
 number = {20}
}

A theory of electronic friction is developed using the exact factorization of the electron-nuclear wavefunction. No assumption is made regarding the electronic bath, which can be made of independent or interacting electrons, and the nuclei are treated quantally. The ensuing equation of motion for the nuclear wavefunction is a non-linear Schr\"odinger equation including a friction term. The resulting friction kernel agrees with a previously derived mixed quantum-classical result by Dou, Miao \& Subotnik (\emphPhys. Rev. Lett. \textbf119, 046001 (2017)), except for a \emphpseudo-magnetic contribution in the latter that is here removed. More specifically, it is shown that the electron dynamics generally washes out the\emph gauge fields appearing in the adiabatic dynamics. However, at T=0 K, the \emphpseudo-magnetic force is fully re-established in the typical situation where the electrons respond rapidy on the slow time-scale of the nuclear dynamics (Markov limit). Hence, we predict Berry's phase effects to be observable also in the presence of electronic friction, and non-trivial geometric phases should be attainable for molecules on metallic magnetic surfaces.

@article{
 title = {Lower Bounds for Nonrelativistic Atomic Energies},
 type = {article},
 year = {2022},
 keywords = {Cauchy−Schwartz inequality,atomic energies,explicitly correlated Gaussians,lower bounds,two- and three-electron atoms},
 pages = {23-37},
 volume = {2},
 websites = {https://pubs.acs.org/doi/full/10.1021/acsphyschemau.1c00018,https://pubs.acs.org/doi/10.1021/acsphyschemau.1c00018},
 month = {1},
 publisher = {American Chemical Society},
 day = {26},
 id = {fabb104c-566f-3e72-addd-fc3ceb3b8f95},
 created = {2022-06-07T10:41:58.928Z},
 accessed = {2022-06-07},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.317Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {A recently developed lower bound theory for Coulombic problems (E. Pollak, R. Martinazzo, J. Chem. Theory Comput. 2021, 17, 1535) is further developed and applied to the highly accurate calculation...},
 bibtype = {article},
 author = {Ireland, Robbie T. and Jeszenszki, Peter and Mátyus, Edit and Martinazzo, Rocco and Ronto, Miklos and Pollak, Eli},
 doi = {10.1021/acsphyschemau.1c00018},
 journal = {ACS Physical Chemistry Au},
 number = {1}
}

A recently developed lower bound theory for Coulombic problems (E. Pollak, R. Martinazzo, J. Chem. Theory Comput. 2021, 17, 1535) is further developed and applied to the highly accurate calculation...

@article{
 title = {Signatures of coherent vibronic exciton dynamics and conformational control in the two-dimensional electronic spectroscopy of conjugated polymers},
 type = {article},
 year = {2022},
 pages = {148-167},
 volume = {237},
 websites = {https://pubs.rsc.org/en/content/articlehtml/2022/fd/d2fd00014h,https://pubs.rsc.org/en/content/articlelanding/2022/fd/d2fd00014h,https://xlink.rsc.org/?DOI=D2FD00014H},
 publisher = {The Royal Society of Chemistry},
 id = {90dc6301-d34e-368c-98a9-6e7a04e0fef4},
 created = {2022-06-07T10:42:23.595Z},
 accessed = {2022-06-07},
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 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
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 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The computation of 2D electronic spectroscopy signals of intra-chain excitons reveals vibronic fine structure due to high-frequency polaronic modes, along with a dynamic Stokes shift induced by soft torsional modes, indicative of exciton motion.},
 bibtype = {article},
 author = {Brey, Dominik and Binder, Robert and Martinazzo, Rocco and Burghardt, Irene},
 doi = {10.1039/D2FD00014H},
 journal = {Faraday Discussions}
}

The computation of 2D electronic spectroscopy signals of intra-chain excitons reveals vibronic fine structure due to high-frequency polaronic modes, along with a dynamic Stokes shift induced by soft torsional modes, indicative of exciton motion.

@article{
 title = {Modelling ultrafast dynamics at a conical intersection with regularized diabatic states: An approach based on multiplicative neural networks},
 type = {article},
 year = {2022},
 pages = {111542},
 volume = {560},
 websites = {https://linkinghub.elsevier.com/retrieve/pii/S0301010422000970},
 month = {8},
 publisher = {North-Holland},
 day = {1},
 id = {87678402-5f05-3260-bab2-a60df1d79c04},
 created = {2022-06-07T10:42:50.238Z},
 accessed = {2022-06-07},
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 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
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 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 bibtype = {article},
 author = {Błasiak, Bartosz and Brey, Dominik and Koch, Werner and Martinazzo, Rocco and Burghardt, Irene},
 doi = {10.1016/J.CHEMPHYS.2022.111542},
 journal = {Chemical Physics}
}

@article{
 title = {Dissipative tunneling rates through the incorporation of first-principles electronic friction in instanton rate theory. I. Theory},
 type = {article},
 year = {2022},
 pages = {194106},
 volume = {156},
 websites = {https://aip.scitation.org/doi/abs/10.1063/5.0088399,https://pubs.aip.org/jcp/article/156/19/194106/2841180/Dissipative-tunneling-rates-through-the},
 month = {5},
 publisher = {AIP Publishing LLCAIP Publishing},
 day = {21},
 id = {40d48538-50e3-3071-ab5d-51f627a35142},
 created = {2022-06-07T10:43:13.622Z},
 accessed = {2022-06-07},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.264Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Reactions involving adsorbates on metallic surfaces and impurities in bulk metals are ubiquitous in a wide range of technological applications. The theoretical modeling of such reactions presents a formidable challenge for theory because nuclear quantum effects (NQEs) can play a prominent role and the coupling of the atomic motion with the electrons in the metal gives rise to important non-adiabatic effects (NAEs) that alter atomic dynamics. In this work, we derive a theoretical framework that captures both NQEs and NAEs and, due to its high efficiency, can be applied to first-principles calculations of reaction rates in high-dimensional realistic systems. More specifically, we develop a method that we coin ring polymer instanton with explicit friction (RPI-EF), starting from the ring polymer instanton formalism applied to a system–bath model. We derive general equations that incorporate the spatial and frequency dependence of the friction tensor and then combine this method with the ab initio electronic friction formalism for the calculation of thermal reaction rates. We show that the connection between RPI-EF and the form of the electronic friction tensor presented in this work does not require any further approximations, and it is expected to be valid as long as the approximations of both underlying theories remain valid.},
 bibtype = {article},
 author = {Litman, Y. and Pós, E. S. and Box, C. L. and Martinazzo, R. and Maurer, R. J. and Rossi, M.},
 doi = {10.1063/5.0088399},
 journal = {The Journal of Chemical Physics},
 number = {19}
}

Reactions involving adsorbates on metallic surfaces and impurities in bulk metals are ubiquitous in a wide range of technological applications. The theoretical modeling of such reactions presents a formidable challenge for theory because nuclear quantum effects (NQEs) can play a prominent role and the coupling of the atomic motion with the electrons in the metal gives rise to important non-adiabatic effects (NAEs) that alter atomic dynamics. In this work, we derive a theoretical framework that captures both NQEs and NAEs and, due to its high efficiency, can be applied to first-principles calculations of reaction rates in high-dimensional realistic systems. More specifically, we develop a method that we coin ring polymer instanton with explicit friction (RPI-EF), starting from the ring polymer instanton formalism applied to a system–bath model. We derive general equations that incorporate the spatial and frequency dependence of the friction tensor and then combine this method with the ab initio electronic friction formalism for the calculation of thermal reaction rates. We show that the connection between RPI-EF and the form of the electronic friction tensor presented in this work does not require any further approximations, and it is expected to be valid as long as the approximations of both underlying theories remain valid.

@article{
 title = {Dissipative tunneling rates through the incorporation of first-principles electronic friction in instanton rate theory. II. Benchmarks and applications},
 type = {article},
 year = {2022},
 pages = {194107},
 volume = {156},
 websites = {https://aip.scitation.org/doi/abs/10.1063/5.0088400,https://pubs.aip.org/jcp/article/156/19/194107/2841188/Dissipative-tunneling-rates-through-the},
 month = {5},
 publisher = {AIP Publishing LLCAIP Publishing},
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 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {In Paper I [Litman et al., J. Chem. Phys. (in press) (2022)], we presented the ring-polymer instanton with explicit friction (RPI-EF) method and showed how it can be connected to the ab initio electronic friction formalism. This framework allows for the calculation of tunneling reaction rates that incorporate the quantum nature of the nuclei and certain types of non-adiabatic effects (NAEs) present in metals. In this paper, we analyze the performance of RPI-EF on model potentials and apply it to realistic systems. For a 1D double-well model, we benchmark the method against numerically exact results obtained from multi-layer multi-configuration time-dependent Hartree calculations. We demonstrate that RPI-EF is accurate for medium and high friction strengths and less accurate for extremely low friction values. We also show quantitatively how the inclusion of NAEs lowers the crossover temperature into the deep tunneling regime, reduces the tunneling rates, and, in certain regimes, steers the quantum dynamics by modifying the tunneling pathways. As a showcase of the efficiency of this method, we present a study of hydrogen and deuterium hopping between neighboring interstitial sites in selected bulk metals. The results show that multidimensional vibrational coupling and nuclear quantum effects have a larger impact than NAEs on the tunneling rates of diffusion in metals. Together with Paper I [Litman et al., J. Chem. Phys. (in press) (2022)], these results advance the calculations of dissipative tunneling rates from first principles.},
 bibtype = {article},
 author = {Litman, Y. and Pós, E. S. and Box, C. L. and Martinazzo, R. and Maurer, R. J. and Rossi, M.},
 doi = {10.1063/5.0088400},
 journal = {The Journal of Chemical Physics},
 number = {19}
}

In Paper I [Litman et al., J. Chem. Phys. (in press) (2022)], we presented the ring-polymer instanton with explicit friction (RPI-EF) method and showed how it can be connected to the ab initio electronic friction formalism. This framework allows for the calculation of tunneling reaction rates that incorporate the quantum nature of the nuclei and certain types of non-adiabatic effects (NAEs) present in metals. In this paper, we analyze the performance of RPI-EF on model potentials and apply it to realistic systems. For a 1D double-well model, we benchmark the method against numerically exact results obtained from multi-layer multi-configuration time-dependent Hartree calculations. We demonstrate that RPI-EF is accurate for medium and high friction strengths and less accurate for extremely low friction values. We also show quantitatively how the inclusion of NAEs lowers the crossover temperature into the deep tunneling regime, reduces the tunneling rates, and, in certain regimes, steers the quantum dynamics by modifying the tunneling pathways. As a showcase of the efficiency of this method, we present a study of hydrogen and deuterium hopping between neighboring interstitial sites in selected bulk metals. The results show that multidimensional vibrational coupling and nuclear quantum effects have a larger impact than NAEs on the tunneling rates of diffusion in metals. Together with Paper I [Litman et al., J. Chem. Phys. (in press) (2022)], these results advance the calculations of dissipative tunneling rates from first principles.

@article{
 title = {Quantum Dynamics with Electronic Friction},
 type = {article},
 year = {2022},
 pages = {206002},
 volume = {128},
 websites = {https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.128.206002,https://link.aps.org/doi/10.1103/PhysRevLett.128.206002},
 month = {5},
 publisher = {American Physical Society},
 day = {20},
 id = {5b3a13b1-6376-3e54-b642-a9f8c0874d98},
 created = {2022-06-07T10:44:56.614Z},
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 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 bibtype = {article},
 author = {Martinazzo, Rocco and Burghardt, Irene},
 doi = {10.1103/PhysRevLett.128.206002},
 journal = {Physical Review Letters},
 number = {20}
}

@article{
 title = {Quantum theory of electronic friction},
 type = {article},
 year = {2022},
 pages = {052215},
 volume = {105},
 websites = {https://journals.aps.org/pra/abstract/10.1103/PhysRevA.105.052215,https://link.aps.org/doi/10.1103/PhysRevA.105.052215},
 month = {5},
 publisher = {American Physical Society},
 day = {20},
 id = {a5e761d1-4cfd-3ff8-849a-85b0b9ae969e},
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 authored = {true},
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 bibtype = {article},
 author = {Martinazzo, Rocco and Burghardt, Irene},
 doi = {10.1103/PhysRevA.105.052215},
 journal = {Physical Review A},
 number = {5}
}

@article{
 title = {Adsorption of Polycyclic Aromatic Hydrocarbons and C 60 onto Forsterite: C–H Bond Activation by the Schottky Vacancy},
 type = {article},
 year = {2022},
 keywords = {PAHs,astrochemistry,catalysis,cosmochemistry,forsterite,fullerene,periodic DFT-D4},
 pages = {2009-2023},
 volume = {6},
 websites = {https://pubs.acs.org/doi/full/10.1021/acsearthspacechem.2c00084,https://pubs.acs.org/doi/10.1021/acsearthspacechem.2c00084},
 month = {8},
 publisher = {American Chemical Society},
 day = {18},
 id = {0954ff7f-f7ec-3c9b-a046-5e0acbcf7a14},
 created = {2022-07-28T18:12:20.486Z},
 accessed = {2022-07-28},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:17.908Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Understanding how to catalytically break the C–H bond of aromatic molecules, such as polycyclic aromatic hydrocarbons (PAHs), is currently a big challenge and a subject of study in catalysis, astro...},
 bibtype = {article},
 author = {Campisi, Dario and Lamberts, Thanja and Dzade, Nelson Y. and Martinazzo, Rocco and ten Kate, Inge Loes and Tielens, Alexander G. G. M.},
 doi = {10.1021/acsearthspacechem.2c00084},
 journal = {ACS Earth and Space Chemistry},
 number = {8}
}

Understanding how to catalytically break the C–H bond of aromatic molecules, such as polycyclic aromatic hydrocarbons (PAHs), is currently a big challenge and a subject of study in catalysis, astro...

@article{
 title = {Interaction of Aromatic Molecules with Forsterite: Accuracy of the Periodic DFT-D4 Method},
 type = {article},
 year = {2021},
 pages = {2770-2781},
 volume = {125},
 websites = {https://pubs.acs.org/doi/full/10.1021/acs.jpca.1c02326,https://pubs.acs.org/doi/10.1021/acs.jpca.1c02326},
 month = {4},
 publisher = {American Chemical Society},
 day = {8},
 id = {263eaf6f-a963-3ae2-8497-478aa9cf6e42},
 created = {2022-06-07T10:38:18.494Z},
 accessed = {2022-06-07},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.105Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Density functional theory (DFT) has provided deep atomic-level insights into the adsorption behavior of aromatic molecules on solid surfaces. However, modeling the surface phenomena of large molecules on mineral surfaces with accurate plane wave methods (PW) can be orders of magnitude more computationally expensive than localized atomic orbitals (LCAO) methods. In the present work, we propose a less costly approach based on the DFT-D4 method (PBE-D4), using LCAO, to study the interactions of aromatic molecules with the 010 forsterite (Mg2SiO4) surface for their relevance in astrochemistry. We studied the interaction of benzene with the pristine 010 forsterite surface and with transition-metal cations (Fe2+ and Ni2+) using PBE-D4 and a vdW-inclusive density functional (Dion, Rydberg, Schröder, Langreth, and Lundqvist (DRSLL)) with LCAO methods. PBE-D4 shows good agreement with coupled-cluster methods (CCSD(T)) for the binding energy trend of cation complexes and with PW methods for the binding energy of benzene on the forsterite surface with a difference of about 0.03 eV. The basis set superposition error (BSSE) correction is shown to be essential to ensure a correct estimation of the binding energies even when large basis sets are employed for single-point calculations of the optimized structures with smaller basis sets. We also studied the interaction of naphthalene and benzocoronene on pristine and transition-metal-doped 010 forsterite surfaces as a test case for PBE-D4. Yielding results that are in good agreement with the plane wave methods with a difference of about 0.02-0.17 eV, the PBE-D4 method is demonstrated to be effective in unraveling the binding structures and the energetic trends of aromatic molecules on pristine and transition-metal-doped forsterite mineral surfaces. Furthermore, PBE-D4 results are in good agreement with its predecessor PBE-D3(BJM) and with the vdW-inclusive density functionals, as long as transition metals are not involved. Hence, PBE-D4/CP-DZP has been proven to be a robust theory level to study the interaction of aromatic molecules on mineral surfaces.},
 bibtype = {article},
 author = {Campisi, Dario and Lamberts, Thanja and Dzade, Nelson Y. and Martinazzo, Rocco and ten Kate, Inge Loes and Tielens, Alexander G. G. M.},
 doi = {10.1021/acs.jpca.1c02326},
 journal = {The Journal of Physical Chemistry A},
 number = {13}
}

Density functional theory (DFT) has provided deep atomic-level insights into the adsorption behavior of aromatic molecules on solid surfaces. However, modeling the surface phenomena of large molecules on mineral surfaces with accurate plane wave methods (PW) can be orders of magnitude more computationally expensive than localized atomic orbitals (LCAO) methods. In the present work, we propose a less costly approach based on the DFT-D4 method (PBE-D4), using LCAO, to study the interactions of aromatic molecules with the 010 forsterite (Mg2SiO4) surface for their relevance in astrochemistry. We studied the interaction of benzene with the pristine 010 forsterite surface and with transition-metal cations (Fe2+ and Ni2+) using PBE-D4 and a vdW-inclusive density functional (Dion, Rydberg, Schröder, Langreth, and Lundqvist (DRSLL)) with LCAO methods. PBE-D4 shows good agreement with coupled-cluster methods (CCSD(T)) for the binding energy trend of cation complexes and with PW methods for the binding energy of benzene on the forsterite surface with a difference of about 0.03 eV. The basis set superposition error (BSSE) correction is shown to be essential to ensure a correct estimation of the binding energies even when large basis sets are employed for single-point calculations of the optimized structures with smaller basis sets. We also studied the interaction of naphthalene and benzocoronene on pristine and transition-metal-doped 010 forsterite surfaces as a test case for PBE-D4. Yielding results that are in good agreement with the plane wave methods with a difference of about 0.02-0.17 eV, the PBE-D4 method is demonstrated to be effective in unraveling the binding structures and the energetic trends of aromatic molecules on pristine and transition-metal-doped forsterite mineral surfaces. Furthermore, PBE-D4 results are in good agreement with its predecessor PBE-D3(BJM) and with the vdW-inclusive density functionals, as long as transition metals are not involved. Hence, PBE-D4/CP-DZP has been proven to be a robust theory level to study the interaction of aromatic molecules on mineral surfaces.

@article{
 title = {Lower Bounds for Coulombic Systems},
 type = {article},
 year = {2021},
 pages = {1535-1547},
 volume = {17},
 websites = {https://pubs.acs.org/doi/full/10.1021/acs.jctc.0c01301,https://pubs.acs.org/doi/10.1021/acs.jctc.0c01301},
 month = {3},
 publisher = {American Chemical Society},
 day = {9},
 id = {05262d9a-6fde-3c40-a9c9-607a935ad130},
 created = {2022-06-07T10:39:10.317Z},
 accessed = {2022-06-07},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.209Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {As of the writing of this paper, lower bounds are not a staple of quantum chemistry computations and for good reason. All previous attempts at applying lower bound theory to Coulombic systems led to lower bounds whose quality was inferior to the Ritz upper bounds so that their added value was minimal. Even our recent improvements upon Temple's lower bound theory were limited to Lanczos basis sets and these are not available to atoms and molecules due to the Coulomb singularity. In the present paper, we overcome these problems by deriving a rather simple eigenvalue equation whose roots, under appropriate conditions, give lower bounds which are competitive with the Ritz upper bounds. The input for the theory is the Ritz eigenvalues and their variances; there is no need to compute the full matrix of the squared Hamiltonian. Along the way, we present a Cauchy-Schwartz inequality which underlies many aspects of lower bound theory. We also show that within the matrix Hamiltonian theory used here, the methods of Lehmann and our recent self-consistent lower bound theory (J. Chem. Phys. 2020, 115, 244110) are identical. Examples include implementation to the hydrogen and helium atoms.},
 bibtype = {article},
 author = {Pollak, Eli and Martinazzo, Rocco},
 doi = {10.1021/acs.jctc.0c01301},
 journal = {Journal of Chemical Theory and Computation},
 number = {3}
}

As of the writing of this paper, lower bounds are not a staple of quantum chemistry computations and for good reason. All previous attempts at applying lower bound theory to Coulombic systems led to lower bounds whose quality was inferior to the Ritz upper bounds so that their added value was minimal. Even our recent improvements upon Temple's lower bound theory were limited to Lanczos basis sets and these are not available to atoms and molecules due to the Coulomb singularity. In the present paper, we overcome these problems by deriving a rather simple eigenvalue equation whose roots, under appropriate conditions, give lower bounds which are competitive with the Ritz upper bounds. The input for the theory is the Ritz eigenvalues and their variances; there is no need to compute the full matrix of the squared Hamiltonian. Along the way, we present a Cauchy-Schwartz inequality which underlies many aspects of lower bound theory. We also show that within the matrix Hamiltonian theory used here, the methods of Lehmann and our recent self-consistent lower bound theory (J. Chem. Phys. 2020, 115, 244110) are identical. Examples include implementation to the hydrogen and helium atoms.

@article{
 title = {Comment on "Regularizing the MCTDH equations of motion through an optimal choice on-the-fly (i.e., spawning) of unoccupied single-particle functions" [D. Mendive-Tapia, H.-D. Meyer, J. Chem. Phys. 153, 234114 (2020)]},
 type = {article},
 year = {2021},
 pages = {234114},
 volume = {153},
 websites = {https://arxiv.org/abs/2102.12117v1},
 month = {2},
 day = {24},
 id = {4c80d3a1-e0ec-3684-8418-8ad712f95dc9},
 created = {2022-06-07T10:39:36.278Z},
 accessed = {2022-06-07},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T10:49:16.262Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The purpose of the present Comment is to point out the connection between an
approach to spawning and regularization that was recently introduced by D.
Mendive-Tapia and H.-D. Meyer [J. Chem. Phys. 153, 234114 (2020)] in the
context of the Multiconfiguration Time-Dependent Hartree (MCTDH) method, and
earlier work where adaptive variational quantum propagation based on the
Local-in-Time Error (LITE) was introduced [R. Martinazzo and I. Burghardt,
Phys. Rev. Lett. 124, 150601 (2020); arXiv:1907.00841 [quant-ph] (2019)].
Furthermore, we show that the LITE represents a gauge-invariant distance which
provides a natural, physically sound tool for adaptive quantum dynamics.},
 bibtype = {article},
 author = {Martinazzo, Rocco and Burghardt, Irene},
 doi = {10.48550/arxiv.2102.12117},
 journal = {J. Chem. Phys}
}

The purpose of the present Comment is to point out the connection between an approach to spawning and regularization that was recently introduced by D. Mendive-Tapia and H.-D. Meyer [J. Chem. Phys. 153, 234114 (2020)] in the context of the Multiconfiguration Time-Dependent Hartree (MCTDH) method, and earlier work where adaptive variational quantum propagation based on the Local-in-Time Error (LITE) was introduced [R. Martinazzo and I. Burghardt, Phys. Rev. Lett. 124, 150601 (2020); arXiv:1907.00841 [quant-ph] (2019)]. Furthermore, we show that the LITE represents a gauge-invariant distance which provides a natural, physically sound tool for adaptive quantum dynamics.

@article{
 title = {Comparison of an improved self-consistent lower bound theory with Lehmann’s method for low-lying eigenvalues},
 type = {article},
 year = {2021},
 keywords = {Ritz eigenvalues,Self-Consistent Lower Bound Theory (SCLBT),energy levels},
 pages = {23450},
 volume = {11},
 websites = {https://doi.org/10.21203/rs.3.rs-492850/v1,https://www.nature.com/articles/s41598-021-02473-y},
 month = {12},
 day = {6},
 id = {7f64dae5-5474-336e-921f-dde83067c9e2},
 created = {2022-06-07T10:39:52.406Z},
 accessed = {2022-06-07},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.207Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Ritz eigenvalues only provide upper bounds for the energy levels, while obtaining lower bounds requires at least the calculation of the variances associated with these eigenvalues. The well-known Weinstein and Temple lower bounds based on the eigenvalues and variances converge very slowly and their quality is considerably worse than that of the Ritz upper bounds. Lehmann presented a method that in principle optimizes Temple’s lower bounds with significantly improved results. We have recently formulated a Self-Consistent Lower Bound Theory (SCLBT), which improves upon Temple’s results. In this paper, we further improve the SCLBT and compare its quality with Lehmann’s theory. The Lánczos algorithm for constructing the Hamiltonian matrix simplifies Lehmann’s theory and is essential for the SCLBT method. Using two lattice Hamiltonians, we compared the improved SCLBT ( i SCLBT) with its previous implementation as well as with Lehmann’s lower bound theory. The novel i SCLBT exhibits a significant improvement over the previous version. Both Lehmann’s theory and the SCLBT variants provide significantly better lower bounds than those obtained from Weinstein’s and Temple’s methods. Compared to each other, the Lehmann and i SCLBT theories exhibit similar performance in terms of the quality and convergence of the lower bounds. By increasing the number of states included in the calculations, the lower bounds are tighter and their quality becomes comparable with that of the Ritz upper bounds. Both methods are suitable for providing lower bounds for low-lying excited states as well. Compared to Lehmann’s theory, one of the advantages of the i SCLBT method is that it does not necessarily require the Weinstein lower bound for its initial input, but Ritz eigenvalue estimates can also be used. Especially owing to this property the i SCLBT method sometimes exhibits improved convergence compared to that of Lehmann’s lower bounds},
 bibtype = {article},
 author = {Ronto, Miklos and Pollak, Eli and Martinazzo, Rocco},
 doi = {10.1038/s41598-021-02473-y},
 journal = {Scientific Reports},
 number = {1}
}

Ritz eigenvalues only provide upper bounds for the energy levels, while obtaining lower bounds requires at least the calculation of the variances associated with these eigenvalues. The well-known Weinstein and Temple lower bounds based on the eigenvalues and variances converge very slowly and their quality is considerably worse than that of the Ritz upper bounds. Lehmann presented a method that in principle optimizes Temple’s lower bounds with significantly improved results. We have recently formulated a Self-Consistent Lower Bound Theory (SCLBT), which improves upon Temple’s results. In this paper, we further improve the SCLBT and compare its quality with Lehmann’s theory. The Lánczos algorithm for constructing the Hamiltonian matrix simplifies Lehmann’s theory and is essential for the SCLBT method. Using two lattice Hamiltonians, we compared the improved SCLBT ( i SCLBT) with its previous implementation as well as with Lehmann’s lower bound theory. The novel i SCLBT exhibits a significant improvement over the previous version. Both Lehmann’s theory and the SCLBT variants provide significantly better lower bounds than those obtained from Weinstein’s and Temple’s methods. Compared to each other, the Lehmann and i SCLBT theories exhibit similar performance in terms of the quality and convergence of the lower bounds. By increasing the number of states included in the calculations, the lower bounds are tighter and their quality becomes comparable with that of the Ritz upper bounds. Both methods are suitable for providing lower bounds for low-lying excited states as well. Compared to Lehmann’s theory, one of the advantages of the i SCLBT method is that it does not necessarily require the Weinstein lower bound for its initial input, but Ritz eigenvalue estimates can also be used. Especially owing to this property the i SCLBT method sometimes exhibits improved convergence compared to that of Lehmann’s lower bounds

@article{
 title = {The Different Story of π Bonds},
 type = {article},
 year = {2021},
 keywords = {DFT,Hubbard,bending,multiple bonding,trans,π distortivity},
 pages = {3805},
 volume = {26},
 websites = {https://www.mdpi.com/1420-3049/26/13/3805/htm,https://www.mdpi.com/1420-3049/26/13/3805},
 month = {6},
 publisher = {Multidisciplinary Digital Publishing Institute},
 day = {22},
 id = {6b809bb3-76db-399d-9608-b3ca46a11dd5},
 created = {2022-06-07T10:40:25.179Z},
 accessed = {2022-06-07},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.133Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {We revisit “classical” issues in multiply bonded systems between main groups elements, namely the structural distortions that may occur at the multiple bonds and that lead, e.g., to trans-bent and bond-length alternated structures. The focus is on the role that orbital hybridization and electron correlation play in this context, here analyzed with the help of simple models for σ- and π-bonds, numerically exact solutions of Hubbard Hamiltonians and first principles (density functional theory) investigations of an extended set of systems.},
 bibtype = {article},
 author = {Cappelletti, Marco and Leccese, Mirko and Cococcioni, Matteo and Proserpio, Davide M. and Martinazzo, Rocco},
 doi = {10.3390/molecules26133805},
 journal = {Molecules},
 number = {13}
}

We revisit “classical” issues in multiply bonded systems between main groups elements, namely the structural distortions that may occur at the multiple bonds and that lead, e.g., to trans-bent and bond-length alternated structures. The focus is on the role that orbital hybridization and electron correlation play in this context, here analyzed with the help of simple models for σ- and π-bonds, numerically exact solutions of Hubbard Hamiltonians and first principles (density functional theory) investigations of an extended set of systems.

@article{
 title = {Comparison of an improved self-consistent lower bound theory with Lehmann’s method for low-lying eigenvalues},
 type = {article},
 year = {2021},
 keywords = {Applied mathematics,Chemical physics,Quantum chemistry},
 pages = {23450},
 volume = {11},
 websites = {https://www.nature.com/articles/s41598-021-02473-y},
 month = {12},
 publisher = {Nature Publishing Group},
 day = {6},
 id = {6346d0d3-d7cf-36bd-8c66-a794edc2c3ab},
 created = {2022-06-07T10:41:06.652Z},
 accessed = {2022-06-07},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.171Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Ritz eigenvalues only provide upper bounds for the energy levels, while obtaining lower bounds requires at least the calculation of the variances associated with these eigenvalues. The well-known Weinstein and Temple lower bounds based on the eigenvalues and variances converge very slowly and their quality is considerably worse than that of the Ritz upper bounds. Lehmann presented a method that in principle optimizes Temple’s lower bounds with significantly improved results. We have recently formulated a Self-Consistent Lower Bound Theory (SCLBT), which improves upon Temple’s results. In this paper, we further improve the SCLBT and compare its quality with Lehmann’s theory. The Lánczos algorithm for constructing the Hamiltonian matrix simplifies Lehmann’s theory and is essential for the SCLBT method. Using two lattice Hamiltonians, we compared the improved SCLBT ( i SCLBT) with its previous implementation as well as with Lehmann’s lower bound theory. The novel i SCLBT exhibits a significant improvement over the previous version. Both Lehmann’s theory and the SCLBT variants provide significantly better lower bounds than those obtained from Weinstein’s and Temple’s methods. Compared to each other, the Lehmann and i SCLBT theories exhibit similar performance in terms of the quality and convergence of the lower bounds. By increasing the number of states included in the calculations, the lower bounds are tighter and their quality becomes comparable with that of the Ritz upper bounds. Both methods are suitable for providing lower bounds for low-lying excited states as well. Compared to Lehmann’s theory, one of the advantages of the i SCLBT method is that it does not necessarily require the Weinstein lower bound for its initial input, but Ritz eigenvalue estimates can also be used. Especially owing to this property the i SCLBT method sometimes exhibits improved convergence compared to that of Lehmann’s lower bounds},
 bibtype = {article},
 author = {Ronto, Miklos and Pollak, Eli and Martinazzo, Rocco},
 doi = {10.1038/s41598-021-02473-y},
 journal = {Scientific Reports},
 number = {1}
}

Ritz eigenvalues only provide upper bounds for the energy levels, while obtaining lower bounds requires at least the calculation of the variances associated with these eigenvalues. The well-known Weinstein and Temple lower bounds based on the eigenvalues and variances converge very slowly and their quality is considerably worse than that of the Ritz upper bounds. Lehmann presented a method that in principle optimizes Temple’s lower bounds with significantly improved results. We have recently formulated a Self-Consistent Lower Bound Theory (SCLBT), which improves upon Temple’s results. In this paper, we further improve the SCLBT and compare its quality with Lehmann’s theory. The Lánczos algorithm for constructing the Hamiltonian matrix simplifies Lehmann’s theory and is essential for the SCLBT method. Using two lattice Hamiltonians, we compared the improved SCLBT ( i SCLBT) with its previous implementation as well as with Lehmann’s lower bound theory. The novel i SCLBT exhibits a significant improvement over the previous version. Both Lehmann’s theory and the SCLBT variants provide significantly better lower bounds than those obtained from Weinstein’s and Temple’s methods. Compared to each other, the Lehmann and i SCLBT theories exhibit similar performance in terms of the quality and convergence of the lower bounds. By increasing the number of states included in the calculations, the lower bounds are tighter and their quality becomes comparable with that of the Ritz upper bounds. Both methods are suitable for providing lower bounds for low-lying excited states as well. Compared to Lehmann’s theory, one of the advantages of the i SCLBT method is that it does not necessarily require the Weinstein lower bound for its initial input, but Ritz eigenvalue estimates can also be used. Especially owing to this property the i SCLBT method sometimes exhibits improved convergence compared to that of Lehmann’s lower bounds

@article{
 title = {Local-in-Time Error in Variational Quantum Dynamics},
 type = {article},
 year = {2020},
 pages = {150601},
 volume = {124},
 websites = {https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.124.150601,https://link.aps.org/doi/10.1103/PhysRevLett.124.150601},
 month = {4},
 publisher = {American Physical Society},
 day = {13},
 id = {2cac1640-e9a6-3b36-b76a-4673e0d3e2ed},
 created = {2022-06-07T10:34:17.763Z},
 accessed = {2022-06-07},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.072Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The McLachlan "minimum-distance" principle for optimizing approximate solutions of the time-dependent Schrödinger equation is revisited, with a focus on the local-in-time error accompanying the variational solutions. Simple, exact expressions are provided for this error, which are then evaluated in illustrative cases, notably the widely used mean-field approach and the adiabatic quantum molecular dynamics. Based on these findings, we demonstrate the rigorous formulation of an adaptive scheme that resizes on the fly the underlying variational manifold and, hence, optimizes the overall computational cost of a quantum dynamical simulation. Such adaptive schemes are a crucial requirement for devising and applying direct quantum dynamical methods to molecular and condensed-phase problems.},
 bibtype = {article},
 author = {Martinazzo, Rocco and Burghardt, Irene},
 doi = {10.1103/PhysRevLett.124.150601},
 journal = {Physical Review Letters},
 number = {15}
}

The McLachlan "minimum-distance" principle for optimizing approximate solutions of the time-dependent Schrödinger equation is revisited, with a focus on the local-in-time error accompanying the variational solutions. Simple, exact expressions are provided for this error, which are then evaluated in illustrative cases, notably the widely used mean-field approach and the adiabatic quantum molecular dynamics. Based on these findings, we demonstrate the rigorous formulation of an adaptive scheme that resizes on the fly the underlying variational manifold and, hence, optimizes the overall computational cost of a quantum dynamical simulation. Such adaptive schemes are a crucial requirement for devising and applying direct quantum dynamical methods to molecular and condensed-phase problems.

@article{
 title = {Lower bounds to eigenvalues of the Schrödinger equation by solution of a 90-y challenge},
 type = {article},
 year = {2020},
 keywords = {Energy eigenstates,Lattice models,Lower bound,Quantum chemistry},
 pages = {16181-16186},
 volume = {117},
 websites = {https://github.com/rocco-martinazzo/LowerBounds.y,https://pnas.org/doi/full/10.1073/pnas.2007093117},
 month = {7},
 publisher = {National Academy of Sciences},
 day = {14},
 id = {e4b74591-5303-3050-bf0c-2a9b5a053022},
 created = {2022-06-07T10:37:08.663Z},
 accessed = {2022-06-07},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.015Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {In quantum theory a celebrated theorem due to Ritz provides upper bounds to eigenvalues of Hermitian operators. An upper bound alone, though, is not sufficient for determining the error of the computed eigenvalues, and cannot be used to assess the quality of energy differences, such as those needed for predicting the position of spectral lines or the energetics of a chemical reaction. The search for a complementary “lower-bound theorem” started in the early days of quantum mechanics but little progress has been reported since a seminal 1928 result of Temple whose accuracy was far less than that of the upper bound. Here, we settle this issue by devising rigorous lower bounds whose accuracy is similar to that of the upper bounds.},
 bibtype = {article},
 author = {Martinazzo, Rocco and Pollak, Eli},
 doi = {10.1073/pnas.2007093117},
 journal = {Proceedings of the National Academy of Sciences},
 number = {28}
}

In quantum theory a celebrated theorem due to Ritz provides upper bounds to eigenvalues of Hermitian operators. An upper bound alone, though, is not sufficient for determining the error of the computed eigenvalues, and cannot be used to assess the quality of energy differences, such as those needed for predicting the position of spectral lines or the energetics of a chemical reaction. The search for a complementary “lower-bound theorem” started in the early days of quantum mechanics but little progress has been reported since a seminal 1928 result of Temple whose accuracy was far less than that of the upper bound. Here, we settle this issue by devising rigorous lower bounds whose accuracy is similar to that of the upper bounds.

@article{
 title = {Self-consistent theory of lower bounds for eigenvalues},
 type = {article},
 year = {2020},
 pages = {244110},
 volume = {152},
 websites = {https://aip.scitation.org/doi/abs/10.1063/5.0009436,https://pubs.aip.org/jcp/article/152/24/244110/1065343/Self-consistent-theory-of-lower-bounds-for},
 month = {6},
 publisher = {AIP Publishing LLCAIP Publishing},
 day = {28},
 id = {53849492-2f3f-388f-aaaa-bd1a03f8dfa9},
 created = {2022-06-07T10:37:30.655Z},
 accessed = {2022-06-07},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.120Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {A rigorous practically applicable theory is presented for obtaining lower bounds to eigenvalues of Hermitian operators, whether the ground state or excited states. Algorithms are presented for computing “residual energies” whose magnitude is essential for the computation of the eigenvalues. Their practical application is possible due to the usage of the Lanczos method for creating a tridiagonal representation of the operator under study. The theory is self-consistent, in the sense that a lower bound for one state may be used to improve the lower bounds for others, and this is then used self-consistently until convergence. The theory is exemplified for a toy model of a quartic oscillator, where with only five states the relative error in the lower bound for the ground state is reduced to 6 · 10−6, which is the same as the relative error of the least upper bound obtained with the same basis functions. The lower bound method presented in this paper suggests that lower bounds may become a staple of eigenvalue computations.},
 bibtype = {article},
 author = {Pollak, Eli and Martinazzo, Rocco},
 doi = {10.1063/5.0009436},
 journal = {The Journal of Chemical Physics},
 number = {24}
}

A rigorous practically applicable theory is presented for obtaining lower bounds to eigenvalues of Hermitian operators, whether the ground state or excited states. Algorithms are presented for computing “residual energies” whose magnitude is essential for the computation of the eigenvalues. Their practical application is possible due to the usage of the Lanczos method for creating a tridiagonal representation of the operator under study. The theory is self-consistent, in the sense that a lower bound for one state may be used to improve the lower bounds for others, and this is then used self-consistently until convergence. The theory is exemplified for a toy model of a quartic oscillator, where with only five states the relative error in the lower bound for the ground state is reduced to 6 · 10−6, which is the same as the relative error of the least upper bound obtained with the same basis functions. The lower bound method presented in this paper suggests that lower bounds may become a staple of eigenvalue computations.

@article{
 title = {Benzodithienyl Silanes for Organic Electronics: AIE Solid‐State Blue Emitters and High Triplet Energy Charge‐Transport Materials},
 type = {article},
 year = {2020},
 keywords = {AIE,OLEDs,benzodithiophenes,blue emitters,host materials,silanes},
 pages = {2001018},
 volume = {8},
 websites = {https://onlinelibrary.wiley.com/doi/full/10.1002/adom.202001018,https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.202001018,https://onlinelibrary.wiley.com/doi/10.1002/adom.202001018},
 month = {11},
 publisher = {John Wiley & Sons, Ltd},
 day = {22},
 id = {4fe2f3cd-0ffa-3a0d-9ab4-00e7956e4539},
 created = {2022-06-07T10:37:50.646Z},
 accessed = {2022-06-07},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.108Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {A novel class of benzo[1,2‐ b :4,3‐ b ′]dithienyl (BDT) silanes 1 – 3 in which a tetrahedral silicon atom connects two BDT units is developed as high triplet energy 3D‐host. The photophysical and electrochemical properties of these structures are investigated, demonstrating that the peculiar features of the constituting BDT units are preserved in the corresponding silanes. All compounds display deep UV absorption ( E g = 4.10–3.52 eV) and fluorescent emission (300–400 nm for 1 and 2 , and 350–450 nm for 3 ). Phosphorescence is observed at low temperature and the respective T 1 states set at 2.65, 2.59, and 2.25 eV. Emission efficiency in solution is as high as 0.18 in 3 . Compound 1 crystallizes in two monoclinic structures without relevant intra‐inter‐molecular contacts; both display similar and intriguing aggregation induced emission‐like deep blue emission (390–397 nm) with quantum yield up to 13%. A blue and a green emissive organic light emitting diode devices are realized using silane 1 as semiconductive host material. The perfect sensitization of the green Ir(ppy) 3 emitter results in a device which nicely compares, in terms of efficiency, with a standard one. The blue FIrpic emitter is instead only partially sensitized on account of the too closed triplets.},
 bibtype = {article},
 author = {Bossi, Alberto and Arnaboldi, Serena and Castellano, Carlo and Martinazzo, Rocco and Cauteruccio, Silvia},
 doi = {10.1002/adom.202001018},
 journal = {Advanced Optical Materials},
 number = {22}
}

A novel class of benzo[1,2‐ b :4,3‐ b ′]dithienyl (BDT) silanes 1 – 3 in which a tetrahedral silicon atom connects two BDT units is developed as high triplet energy 3D‐host. The photophysical and electrochemical properties of these structures are investigated, demonstrating that the peculiar features of the constituting BDT units are preserved in the corresponding silanes. All compounds display deep UV absorption ( E g = 4.10–3.52 eV) and fluorescent emission (300–400 nm for 1 and 2 , and 350–450 nm for 3 ). Phosphorescence is observed at low temperature and the respective T 1 states set at 2.65, 2.59, and 2.25 eV. Emission efficiency in solution is as high as 0.18 in 3 . Compound 1 crystallizes in two monoclinic structures without relevant intra‐inter‐molecular contacts; both display similar and intriguing aggregation induced emission‐like deep blue emission (390–397 nm) with quantum yield up to 13%. A blue and a green emissive organic light emitting diode devices are realized using silane 1 as semiconductive host material. The perfect sensitization of the green Ir(ppy) 3 emitter results in a device which nicely compares, in terms of efficiency, with a standard one. The blue FIrpic emitter is instead only partially sensitized on account of the too closed triplets.

@article{
 title = {Superhydrogenation of pentacene: the reactivity of zigzag-edges},
 type = {article},
 year = {2020},
 pages = {1557-1565},
 volume = {22},
 websites = {https://pubs.rsc.org/en/content/articlehtml/2020/cp/c9cp05440e,https://pubs.rsc.org/en/content/articlelanding/2020/cp/c9cp05440e,https://xlink.rsc.org/?DOI=C9CP05440E},
 month = {1},
 publisher = {The Royal Society of Chemistry},
 day = {22},
 id = {679e1d94-e76a-3364-a6ea-9f060289969e},
 created = {2022-06-07T13:52:43.117Z},
 accessed = {2022-06-07},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:17.908Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Studies of pentacene hydrogenation reveal a preferential hydrogenation sequence. The guiding concepts apply more broadly to aromatic carbonaceous systems and may be crucial in catalytic formation of molecular hydrogen in interstellar space.},
 bibtype = {article},
 author = {Campisi, Dario and Simonsen, Frederik Doktor S. and Thrower, John D. and Jaganathan, Rijutha and Hornekær, Liv and Martinazzo, Rocco and Tielens, Alexander G. G. M.},
 doi = {10.1039/C9CP05440E},
 journal = {Physical Chemistry Chemical Physics},
 number = {3}
}

Studies of pentacene hydrogenation reveal a preferential hydrogenation sequence. The guiding concepts apply more broadly to aromatic carbonaceous systems and may be crucial in catalytic formation of molecular hydrogen in interstellar space.

@article{
 title = {Dual-Route Hydrogenation of the Graphene/Ni Interface},
 type = {article},
 year = {2019},
 keywords = {Desorption,Graphene,Hydrogenation,Intercalation,Nickel,Storage},
 pages = {acsnano.8b07996},
 volume = {13},
 websites = {https://pubs.acs.org/doi/full/10.1021/acsnano.8b07996,https://pubs.acs.org/doi/10.1021/acsnano.8b07996},
 month = {1},
 publisher = {American Chemical Society},
 day = {22},
 id = {43f7389d-b0a0-32f1-a83c-468001a57378},
 created = {2022-06-08T07:24:06.894Z},
 accessed = {2022-06-08},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-19T11:58:44.982Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Nanostructured architectures based on graphene/metal interfaces might be efficiently exploited in hydrogen storage due to the attractive capability to provide adsorption sites both at the top side of graphene and at the metal substrate after intercalation. We combined in situ high-resolution X-ray photoelectron spectroscopy and scanning tunneling microscopy with theoretical calculations to determine the arrangement of hydrogen atoms at the graphene/Ni(111) interface at room temperature. Our results show that at low coverage H atoms predominantly adsorb as monomers and that chemisorption saturates when â25% of the surface is hydrogenated. In parallel, with a much lower rate, H atoms intercalate below graphene and bind to Ni surface sites. Intercalation progressively destabilizes the C-H bonds and triggers the release of the hydrogen chemisorbed on graphene. Valence band and near-edge absorption spectroscopy demonstrate that the graphene layer is fully lifted when the Ni surface is saturated with H. Thermal programmed desorption was used to determine the stability of the hydrogenated interface. Whereas the H atoms chemisorbed on graphene remain unperturbed over a wide temperature range, the intercalated phase abruptly desorbs 50-100 K above room temperature.},
 bibtype = {article},
 author = {Lizzit, Daniel and Trioni, Mario I. and Bignardi, Luca and Lacovig, Paolo and Lizzit, Silvano and Martinazzo, Rocco and Larciprete, Rosanna},
 doi = {10.1021/acsnano.8b07996},
 journal = {ACS Nano},
 number = {2}
}

Nanostructured architectures based on graphene/metal interfaces might be efficiently exploited in hydrogen storage due to the attractive capability to provide adsorption sites both at the top side of graphene and at the metal substrate after intercalation. We combined in situ high-resolution X-ray photoelectron spectroscopy and scanning tunneling microscopy with theoretical calculations to determine the arrangement of hydrogen atoms at the graphene/Ni(111) interface at room temperature. Our results show that at low coverage H atoms predominantly adsorb as monomers and that chemisorption saturates when â25% of the surface is hydrogenated. In parallel, with a much lower rate, H atoms intercalate below graphene and bind to Ni surface sites. Intercalation progressively destabilizes the C-H bonds and triggers the release of the hydrogen chemisorbed on graphene. Valence band and near-edge absorption spectroscopy demonstrate that the graphene layer is fully lifted when the Ni surface is saturated with H. Thermal programmed desorption was used to determine the stability of the hydrogenated interface. Whereas the H atoms chemisorbed on graphene remain unperturbed over a wide temperature range, the intercalated phase abruptly desorbs 50-100 K above room temperature.

@article{
 title = {To bend or not to bend, the dilemma of multiple bonds},
 type = {article},
 year = {2019},
 pages = {26342-26350},
 volume = {21},
 websites = {https://pubs.rsc.org/en/content/articlehtml/2019/cp/c9cp05192a,https://pubs.rsc.org/en/content/articlelanding/2019/cp/c9cp05192a},
 month = {12},
 publisher = {The Royal Society of Chemistry},
 day = {11},
 id = {6416b5f3-d811-314e-a011-48b9bf3b947a},
 created = {2022-06-08T07:28:26.332Z},
 accessed = {2022-06-08},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-08T07:36:19.529Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Beyond the second row of the periodic table, the nature of the multiple bonds between the elements of the main groups remains yet elusive, and “non-classical” bonding schemes are often invoked for their description. Here, focusing on group 14, we have performed an accurate modeling of the Si–Si and C–C double bonds, including electron correlation effects. We have shown that SiSi bonds are “classical” and closely resemble CC ones, being similarly subjected to a sort of tug of war in which the σ bond favors distortion and the π bond opposes it. The essential difference between Si and C boils down to the sizes of their valence shells, which determine the π-bending stiffness. In carbon, such a stiffness is large because, upon bending, the atomic s orbitals interfere destructively with the p ones. In silicon, the s shell is smaller than the p one, the bending stiffness is reduced and the π bonds typically succumb, distort, and weaken. Electron correlation plays a major role in this context, since π bonds are far from their molecular orbital limit. Hence, we have further shown that upon weakening the effective repulsion between π electrons one may remove any structural instability, strengthen the π bonds and turn Si into a closer relative of C than it used to be.},
 bibtype = {article},
 author = {Pizzochero, Michele and Bonfanti, Matteo and Martinazzo, Rocco},
 doi = {10.1039/C9CP05192A},
 journal = {Physical Chemistry Chemical Physics},
 number = {48}
}

Beyond the second row of the periodic table, the nature of the multiple bonds between the elements of the main groups remains yet elusive, and “non-classical” bonding schemes are often invoked for their description. Here, focusing on group 14, we have performed an accurate modeling of the Si–Si and C–C double bonds, including electron correlation effects. We have shown that SiSi bonds are “classical” and closely resemble CC ones, being similarly subjected to a sort of tug of war in which the σ bond favors distortion and the π bond opposes it. The essential difference between Si and C boils down to the sizes of their valence shells, which determine the π-bending stiffness. In carbon, such a stiffness is large because, upon bending, the atomic s orbitals interfere destructively with the p ones. In silicon, the s shell is smaller than the p one, the bending stiffness is reduced and the π bonds typically succumb, distort, and weaken. Electron correlation plays a major role in this context, since π bonds are far from their molecular orbital limit. Hence, we have further shown that upon weakening the effective repulsion between π electrons one may remove any structural instability, strengthen the π bonds and turn Si into a closer relative of C than it used to be.

@article{
 title = {Kinetic model for the ammoxidation of ethanol to acetonitrile},
 type = {article},
 year = {2019},
 keywords = {Acetonitrile,Ammoxidation,Biorefinery,Ethanol,Kinetic modeling},
 pages = {862-875},
 volume = {207},
 month = {11},
 publisher = {Pergamon},
 day = {2},
 id = {faa561a9-c33a-3aac-b507-b2b95b5a5531},
 created = {2022-06-08T07:29:29.397Z},
 accessed = {2022-06-08},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-08T07:36:19.401Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {A comprehensive kinetic study, based on V-based catalysts (Vanadium Pyro-Phosphate, VPP, VOx/TiO2 and VOx/ZrO2), was modeled to retrieve the surface reaction mechanism and kinetic parameters for the ammoxidation of ethanol to acetonitrile. In all the cases, the catalysts showed a moderate to good acetonitrile selectivity, that in turn resulted correlated primarily to the reaction temperature, while the byproducts distribution was more influenced by the thermodynamic stability of the reacting mixture. A large and comprehensive collection of data on ammoxidation of C2 substrates for acetonitrile production was analysed and 5 groups of experiments on VOx-based catalysts (operating in the temperature range 250–450 °C) were selected. The base reactant was ethanol and ammonia and oxygen were fed in optimal ratios of 1:3–1:4 mol/mol. A kinetic model was then derived applying the Langmuir-Hinshelwood-Hougen-Watson (LHHW) approach to accepted catalytic oxidation mechanisms: for every catalytic material, eight to ten reactions with rates described by the Arrhenius formula were employed. Fixing the reaction orders according to the mechanistic assumption and adjusting only the kinetic and adsorption parameters, the calculated molar fractions of ethanol, ammonia, acetonitrile and ethylene resulted in good agreement with the extensive collection of experimental data available.},
 bibtype = {article},
 author = {Tripodi, Antonio and Ripamonti, Davide and Martinazzo, R. and Folco, Federico and Tabanelli, Tommaso and Cavani, Fabrizio and Rossetti, Ilenia},
 doi = {10.1016/J.CES.2019.07.015},
 journal = {Chemical Engineering Science}
}

A comprehensive kinetic study, based on V-based catalysts (Vanadium Pyro-Phosphate, VPP, VOx/TiO2 and VOx/ZrO2), was modeled to retrieve the surface reaction mechanism and kinetic parameters for the ammoxidation of ethanol to acetonitrile. In all the cases, the catalysts showed a moderate to good acetonitrile selectivity, that in turn resulted correlated primarily to the reaction temperature, while the byproducts distribution was more influenced by the thermodynamic stability of the reacting mixture. A large and comprehensive collection of data on ammoxidation of C2 substrates for acetonitrile production was analysed and 5 groups of experiments on VOx-based catalysts (operating in the temperature range 250–450 °C) were selected. The base reactant was ethanol and ammonia and oxygen were fed in optimal ratios of 1:3–1:4 mol/mol. A kinetic model was then derived applying the Langmuir-Hinshelwood-Hougen-Watson (LHHW) approach to accepted catalytic oxidation mechanisms: for every catalytic material, eight to ten reactions with rates described by the Arrhenius formula were employed. Fixing the reaction orders according to the mechanistic assumption and adjusting only the kinetic and adsorption parameters, the calculated molar fractions of ethanol, ammonia, acetonitrile and ethylene resulted in good agreement with the extensive collection of experimental data available.

@article{
 title = {Identification of stable configurations in the superhydrogenation sequence of polycyclic aromatic hydrocarbon molecules},
 type = {article},
 year = {2019},
 keywords = {ISM: clouds,ISM: molecules,Photodissociation region},
 pages = {5492-5498},
 volume = {486},
 websites = {https://academic.oup.com/mnras/article/486/4/5492/5484867},
 month = {7},
 publisher = {Oxford Academic},
 day = {11},
 id = {a1b6009a-6391-34b9-bea5-b270c77088e4},
 created = {2022-06-08T07:30:48.100Z},
 accessed = {2022-06-08},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-08T07:36:19.792Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Superhydrogenated polycyclic aromatic hydrocarbon (PAH) molecules have been demonstrated to act as catalysts for molecular hydrogen formation under interstellar conditions. Here we present combined thermal desorption mass spectrometry measurements and density functional theory calculations that reveal the most stable configurations in the superhydrogenation sequence of the PAH molecule coronene (C24H12). Specifically, the experiments demonstrate the presence of stable configurations of superhydrogenated coronene at specific hydrogenation levels of 2, 10, 14, 18, and 24 extra hydrogen atoms. Density functional theory calculations of binding energies and barrier heights explain why these configurations are particularly stable and provide new insights into the superhydrogenation process of PAH molecules under interstellar conditions. Furthermore, an experimental cross-section for the first hydrogen atom addition to the neutral coronene molecule of σadd = 2.7+2.7-0.9 × 10-2 A2 is derived from the experimental hydrogenation data.},
 bibtype = {article},
 author = {Jensen, Pernille A. and Leccese, Mirko and Simonsen, Frederik D.S. and Skov, Anders W. and Bonfanti, Matteo and Thrower, John D. and Martinazzo, Rocco and Hornekær, Liv},
 doi = {10.1093/MNRAS/STZ1202},
 journal = {Monthly Notices of the Royal Astronomical Society},
 number = {4}
}

Superhydrogenated polycyclic aromatic hydrocarbon (PAH) molecules have been demonstrated to act as catalysts for molecular hydrogen formation under interstellar conditions. Here we present combined thermal desorption mass spectrometry measurements and density functional theory calculations that reveal the most stable configurations in the superhydrogenation sequence of the PAH molecule coronene (C24H12). Specifically, the experiments demonstrate the presence of stable configurations of superhydrogenated coronene at specific hydrogenation levels of 2, 10, 14, 18, and 24 extra hydrogen atoms. Density functional theory calculations of binding energies and barrier heights explain why these configurations are particularly stable and provide new insights into the superhydrogenation process of PAH molecules under interstellar conditions. Furthermore, an experimental cross-section for the first hydrogen atom addition to the neutral coronene molecule of σadd = 2.7+2.7-0.9 × 10-2 A2 is derived from the experimental hydrogenation data.

@article{
 title = {Vibronic coupling models for donor-acceptor aggregates using an effective-mode scheme: Application to mixed Frenkel and charge-transfer excitons in oligothiophene aggregates},
 type = {article},
 year = {2019},
 pages = {244114},
 volume = {150},
 websites = {https://aip.scitation.org/doi/abs/10.1063/1.5100529,https://pubs.aip.org/jcp/article/150/24/244114/197992/Vibronic-coupling-models-for-donor-acceptor},
 month = {6},
 publisher = {AIP Publishing LLCAIP Publishing},
 day = {28},
 id = {38d3c168-18a3-35d0-bfbb-a8195f37282e},
 created = {2022-06-08T07:31:11.985Z},
 accessed = {2022-06-08},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:17.903Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {A reduced-dimensional effective-mode representation is developed in order to efficiently describe excited-state dynamics of multichromophoric donor-acceptor aggregates within a linear vibronic coupling model. Specifically, we consider systems where vibrational modes pertaining to a given molecular fragment couple both to local excitations of Frenkel type and delocalized states of charge transfer exciton type. A hierarchical chain representation is constructed which is suitable to describe correlated fluctuations, leading to a set of correlated spectral densities. An application is shown for a first-principles parameterized model of an oligothiophene H-type aggregate whose properties are modified due to the presence of charge transfer excitons. Within a pentamer model comprising 13 electronic states and 195 normal modes, good convergence of the effective-mode representation of the spectral densities is achieved at the eighth order of the hierarchy with 104 modes, and a qualitatively correct picture is obtained at the sixth order with 78 modes.},
 bibtype = {article},
 author = {Popp, Wjatscheslaw and Polkehn, Matthias and Hughes, Keith H. and Martinazzo, Rocco and Burghardt, Irene},
 doi = {10.1063/1.5100529},
 journal = {The Journal of Chemical Physics},
 number = {24}
}

A reduced-dimensional effective-mode representation is developed in order to efficiently describe excited-state dynamics of multichromophoric donor-acceptor aggregates within a linear vibronic coupling model. Specifically, we consider systems where vibrational modes pertaining to a given molecular fragment couple both to local excitations of Frenkel type and delocalized states of charge transfer exciton type. A hierarchical chain representation is constructed which is suitable to describe correlated fluctuations, leading to a set of correlated spectral densities. An application is shown for a first-principles parameterized model of an oligothiophene H-type aggregate whose properties are modified due to the presence of charge transfer excitons. Within a pentamer model comprising 13 electronic states and 195 normal modes, good convergence of the effective-mode representation of the spectral densities is achieved at the eighth order of the hierarchy with 104 modes, and a qualitatively correct picture is obtained at the sixth order with 78 modes.

@article{
 title = {Full quantum dynamical investigation of the Eley–Rideal reaction forming H2 on a movable graphitic substrate at T = 0 K},
 type = {article},
 year = {2018},
 pages = {977-988},
 volume = {20},
 websites = {https://pubs.rsc.org/en/content/articlehtml/2018/cp/c7cp07080b,https://pubs.rsc.org/en/content/articlelanding/2018/cp/c7cp07080b},
 month = {1},
 publisher = {The Royal Society of Chemistry},
 day = {3},
 id = {ef5a0326-d41f-378b-96df-6956560842ba},
 created = {2022-06-08T07:39:10.083Z},
 accessed = {2022-06-08},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-08T07:41:44.275Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The dynamics of the Eley–Rideal abstraction reaction of hydrogen atoms on a movable graphitic surface is investigated for the first time in a numerically exact fully quantum setting. A system-bath strategy was applied where the two recombining H atoms and a substrate C atom form a relevant subsystem, while the rest of the lattice takes the form of an independent oscillator bath. High-dimensional wavepacket simulations were performed in the collision energy range 0.2–1.0 eV with the help of the multi-layer multi-configuration time-dependent Hartree method, focusing on the collinear reaction on a zero-temperature surface. Results show that the dynamics is close to a sudden limit in which the reaction is much faster than the substrate motion. Unpuckering of the surface is fast (some tens of fs) but starts only after the formation of H2 is completed, thereby determining a considerable substrate heating (∼0.8 eV per reactive event). Energy partitioning in the product molecule favors translational over vibrational energy, and H2 molecules are vibrationally hot (∼1.5 eV) though to a lesser extent than previously predicted.},
 bibtype = {article},
 author = {Pasquini, Marta and Bonfanti, Matteo and Martinazzo, Rocco},
 doi = {10.1039/C7CP07080B},
 journal = {Physical Chemistry Chemical Physics},
 number = {2}
}

The dynamics of the Eley–Rideal abstraction reaction of hydrogen atoms on a movable graphitic surface is investigated for the first time in a numerically exact fully quantum setting. A system-bath strategy was applied where the two recombining H atoms and a substrate C atom form a relevant subsystem, while the rest of the lattice takes the form of an independent oscillator bath. High-dimensional wavepacket simulations were performed in the collision energy range 0.2–1.0 eV with the help of the multi-layer multi-configuration time-dependent Hartree method, focusing on the collinear reaction on a zero-temperature surface. Results show that the dynamics is close to a sudden limit in which the reaction is much faster than the substrate motion. Unpuckering of the surface is fast (some tens of fs) but starts only after the formation of H2 is completed, thereby determining a considerable substrate heating (∼0.8 eV per reactive event). Energy partitioning in the product molecule favors translational over vibrational energy, and H2 molecules are vibrationally hot (∼1.5 eV) though to a lesser extent than previously predicted.

@article{
 title = {Comment on "theoretical study of the dynamics of atomic hydrogen adsorbed on graphene multilayers"},
 type = {article},
 year = {2018},
 pages = {117401},
 volume = {97},
 websites = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.97.117401},
 month = {3},
 publisher = {American Physical Society},
 day = {21},
 id = {f582aef1-e367-32e5-b793-81ced9784ba8},
 created = {2022-06-08T07:39:12.187Z},
 accessed = {2022-06-08},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-08T07:41:44.300Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {It is shown that the theoretical prediction of a transient magnetization in bilayer and multilayer graphene (M. Moaied, Phys. Rev. B 91, 155419 (2015)PRBMDO1098-012110.1103/PhysRevB.91.155419) relies on an incorrect physical scenario for adsorption, namely, one in which H atoms adsorb barrierless on graphitic substrates and form a random adsorption pattern of monomers. Rather, according to experimental evidence, H atom sticking is an activated process, and adsorption is under kinetic control, largely ruled by a preferential sticking mechanism that leads to stable, nonmagnetic dimers at all but the smallest coverages (<0.004). Theory and experiments are reconciled by reconsidering the hydrogen atom adsorption energetics with the help of van der Waals-inclusive density functional calculations that properly account for the basis set superposition error. It is shown that today van der Waals-density functional theory predicts a shallow physisorption well that nicely agrees with available experimental data and suggests that the hydrogen atom adsorption barrier in graphene is 180 meV high, within ∼5 meV accuracy.},
 bibtype = {article},
 author = {Bonfanti, Matteo and Martinazzo, Rocco},
 doi = {10.1103/PHYSREVB.97.117401/FIGURES/4/MEDIUM},
 journal = {Physical Review B},
 number = {11}
}

It is shown that the theoretical prediction of a transient magnetization in bilayer and multilayer graphene (M. Moaied, Phys. Rev. B 91, 155419 (2015)PRBMDO1098-012110.1103/PhysRevB.91.155419) relies on an incorrect physical scenario for adsorption, namely, one in which H atoms adsorb barrierless on graphitic substrates and form a random adsorption pattern of monomers. Rather, according to experimental evidence, H atom sticking is an activated process, and adsorption is under kinetic control, largely ruled by a preferential sticking mechanism that leads to stable, nonmagnetic dimers at all but the smallest coverages (<0.004). Theory and experiments are reconciled by reconsidering the hydrogen atom adsorption energetics with the help of van der Waals-inclusive density functional calculations that properly account for the basis set superposition error. It is shown that today van der Waals-density functional theory predicts a shallow physisorption well that nicely agrees with available experimental data and suggests that the hydrogen atom adsorption barrier in graphene is 180 meV high, within ∼5 meV accuracy.

@article{
 title = {Sticking of atomic hydrogen on graphene},
 type = {article},
 year = {2018},
 keywords = {adsorption,magnetism,reaction,transport},
 pages = {283002},
 volume = {30},
 websites = {https://iopscience.iop.org/article/10.1088/1361-648X/aac89f,https://iopscience.iop.org/article/10.1088/1361-648X/aac89f/meta},
 month = {6},
 publisher = {IOP Publishing},
 day = {20},
 id = {47fde973-574f-39c3-9abc-42c471aa6c95},
 created = {2022-06-08T07:39:15.969Z},
 accessed = {2022-06-08},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-08T07:41:44.314Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Recent years have witnessed an ever growing interest in the interactions between hydrogen atoms and a graphene sheet. Largely motivated by the possibility of modulating the electric, optical and magnetic properties of graphene, a huge number of studies have appeared recently that added to and enlarged earlier investigations on graphite and other carbon materials. In this review we give a glimpse of the many facets of this adsorption process, as they emerged from these studies. The focus is on those issues that have been addressed in detail, under carefully controlled conditions, with an emphasis on the interplay between the adatom structures, their formation dynamics and the electric, magnetic and chemical properties of the carbon sheet.},
 bibtype = {article},
 author = {Bonfanti, Matteo and Achilli, Simona and Martinazzo, Rocco},
 doi = {10.1088/1361-648X/AAC89F},
 journal = {Journal of Physics: Condensed Matter},
 number = {28}
}

Recent years have witnessed an ever growing interest in the interactions between hydrogen atoms and a graphene sheet. Largely motivated by the possibility of modulating the electric, optical and magnetic properties of graphene, a huge number of studies have appeared recently that added to and enlarged earlier investigations on graphite and other carbon materials. In this review we give a glimpse of the many facets of this adsorption process, as they emerged from these studies. The focus is on those issues that have been addressed in detail, under carefully controlled conditions, with an emphasis on the interplay between the adatom structures, their formation dynamics and the electric, magnetic and chemical properties of the carbon sheet.

@article{
 title = {Process Simulation for the Design and Scale Up of Heterogeneous Catalytic Process: Kinetic Modelling Issues},
 type = {article},
 year = {2017},
 keywords = {ammonia,bioethanol,ethylene,kinetic modelling,methanol,process simulation,steam reforming},
 pages = {159},
 volume = {7},
 websites = {https://www.mdpi.com/2073-4344/7/5/159/htm,https://www.mdpi.com/2073-4344/7/5/159},
 month = {5},
 publisher = {Multidisciplinary Digital Publishing Institute},
 day = {18},
 id = {84526876-50bf-36b0-903a-d93b686cd466},
 created = {2022-06-08T07:42:24.236Z},
 accessed = {2022-06-08},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-08T07:43:37.532Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Process simulation represents an important tool for plant design and optimization, either applied to well established or to newly developed processes. Suitable thermodynamic packages should be selected in order to properly describe the behavior of reactors and unit operations and to precisely define phase equilibria. Moreover, a detailed and representative kinetic scheme should be available to predict correctly the dependence of the process on its main variables. This review points out some models and methods for kinetic analysis specifically applied to the simulation of catalytic processes, as a basis for process design and optimization. Attention is paid also to microkinetic modelling and to the methods based on first principles, to elucidate mechanisms and independently calculate thermodynamic and kinetic parameters. Different case studies support the discussion. At first, we have selected two basic examples from the industrial chemistry practice, e.g., ammonia and methanol synthesis, which may be described through a relatively simple reaction pathway and the relative available kinetic scheme. Then, a more complex reaction network is deeply discussed to define the conversion of bioethanol into syngas/hydrogen or into building blocks, such as ethylene. In this case, lumped kinetic schemes completely fail the description of process behavior. Thus, in this case, more detailed—e.g., microkinetic—schemes should be available to implement into the simulator. However, the correct definition of all the kinetic data when complex microkinetic mechanisms are used, often leads to unreliable, highly correlated parameters. In such cases, greater effort to independently estimate some relevant kinetic/thermodynamic data through Density Functional Theory (DFT)/ab initio methods may be helpful to improve process description.},
 bibtype = {article},
 author = {Tripodi, Antonio and Compagnoni, Matteo and Martinazzo, Rocco and Ramis, Gianguido and Rossetti, Ilenia},
 doi = {10.3390/CATAL7050159},
 journal = {Catalysts 2017, Vol. 7, Page 159},
 number = {5}
}

Process simulation represents an important tool for plant design and optimization, either applied to well established or to newly developed processes. Suitable thermodynamic packages should be selected in order to properly describe the behavior of reactors and unit operations and to precisely define phase equilibria. Moreover, a detailed and representative kinetic scheme should be available to predict correctly the dependence of the process on its main variables. This review points out some models and methods for kinetic analysis specifically applied to the simulation of catalytic processes, as a basis for process design and optimization. Attention is paid also to microkinetic modelling and to the methods based on first principles, to elucidate mechanisms and independently calculate thermodynamic and kinetic parameters. Different case studies support the discussion. At first, we have selected two basic examples from the industrial chemistry practice, e.g., ammonia and methanol synthesis, which may be described through a relatively simple reaction pathway and the relative available kinetic scheme. Then, a more complex reaction network is deeply discussed to define the conversion of bioethanol into syngas/hydrogen or into building blocks, such as ethylene. In this case, lumped kinetic schemes completely fail the description of process behavior. Thus, in this case, more detailed—e.g., microkinetic—schemes should be available to implement into the simulator. However, the correct definition of all the kinetic data when complex microkinetic mechanisms are used, often leads to unreliable, highly correlated parameters. In such cases, greater effort to independently estimate some relevant kinetic/thermodynamic data through Density Functional Theory (DFT)/ab initio methods may be helpful to improve process description.

@article{
 title = {A family of solution-processable macrocyclic and open-chain oligothiophenes with atropoisomeric scaffolds: structural and electronic features for potential energy applications},
 type = {article},
 year = {2017},
 pages = {10009-10019},
 volume = {41},
 websites = {https://pubs.rsc.org/en/content/articlehtml/2017/nj/c7nj01501a,https://pubs.rsc.org/en/content/articlelanding/2017/nj/c7nj01501a},
 month = {9},
 publisher = {The Royal Society of Chemistry},
 day = {11},
 id = {e23d7d27-092a-3184-b65b-2545fdce6d3e},
 created = {2022-06-08T07:42:27.372Z},
 accessed = {2022-06-08},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-08T07:43:37.576Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {FeCl3 oxidation of the racemate of C2 symmetric, inherently chiral, sexithiophene monomer 1 (2,2′-bis(2,2′-bithiophene-5-yl)-3,3′-bithianaphthene) affords a mixture of cyclic oligomers, from the prevailing dimer to traces of the pentamer. The oligomers are constituted by mixtures of stereoisomers which are two for dimer 2, four for trimer 3 and six for tetramer 4. Cyclooligomers 2 and 3 could be separated by chromatography, while 4 was synthesized by ring closure of open chain dimer 2a, prepared in turn by controlled coupling of the anion of racemic 1. The optical properties of open-chain stereoisomer 2a and tetramer 4 have been compared with those of 2 and 3 respectively. The macrocyclic oligomers have been tested as donor materials in bulk heterojunction solar cell prototypes both as a crude mixture resulting from oxidation of 1 and as a single oligomer. Theoretical calculations support the photophysical properties of these new materials.},
 bibtype = {article},
 author = {Quartapelle Procopio, E. and Benincori, T. and Appoloni, G. and Mussini, P. R. and Arnaboldi, S. and Carbonera, C. and Cirilli, R. and Cominetti, A. and Longo, L. and Martinazzo, R. and Panigati, M. and Pò, R.},
 doi = {10.1039/C7NJ01501A},
 journal = {New Journal of Chemistry},
 number = {18}
}

FeCl3 oxidation of the racemate of C2 symmetric, inherently chiral, sexithiophene monomer 1 (2,2′-bis(2,2′-bithiophene-5-yl)-3,3′-bithianaphthene) affords a mixture of cyclic oligomers, from the prevailing dimer to traces of the pentamer. The oligomers are constituted by mixtures of stereoisomers which are two for dimer 2, four for trimer 3 and six for tetramer 4. Cyclooligomers 2 and 3 could be separated by chromatography, while 4 was synthesized by ring closure of open chain dimer 2a, prepared in turn by controlled coupling of the anion of racemic 1. The optical properties of open-chain stereoisomer 2a and tetramer 4 have been compared with those of 2 and 3 respectively. The macrocyclic oligomers have been tested as donor materials in bulk heterojunction solar cell prototypes both as a crude mixture resulting from oxidation of 1 and as a single oligomer. Theoretical calculations support the photophysical properties of these new materials.

@article{
 title = {Classical and quantum dynamics at surfaces: Basic concepts from simple models},
 type = {article},
 year = {2016},
 keywords = {Atom,Eley,Hot,Rideal,dissipative quantum dynamics,gas,surface dynamics,surface scattering},
 pages = {1575-1602},
 volume = {116},
 websites = {https://onlinelibrary.wiley.com/doi/full/10.1002/qua.25192,https://onlinelibrary.wiley.com/doi/abs/10.1002/qua.25192,https://onlinelibrary.wiley.com/doi/10.1002/qua.25192},
 month = {11},
 publisher = {John Wiley & Sons, Ltd},
 day = {5},
 id = {cd62baae-f485-3476-b3b3-7e9b39394f6d},
 created = {2022-06-10T13:23:17.950Z},
 accessed = {2022-06-10},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-10T13:28:11.968Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Elementary processes involving atomic and molecular species at surfaces are reviewed. The emphasis is on simple classical and quantum models that help to single out unifying dynamical themes and to identify the basic physical mechanisms that underlie the rich variety of phenomena of surface chemistry. Starting from an elementary description of the energy transfer between a gas-phase species and a surface—for both classical and quantum lattices—the key processes establishing the formation of an adsorbed phase (sticking, diffusion and vibrational relaxation) are discussed. This is instrumental for introducing the simplest chemical transformations involving adsorbed species and/or scattering of gas-phase molecules: Langmuir–Hinshelwood, Hot-Atom, and Eley–Rideal reactions forming complex molecules from elementary constituents, and dissociative chemisorption of molecules into smaller fragments. Applications are also provided illustrating the ideas developed along the way at work in real-world gas-surface problems.},
 bibtype = {article},
 author = {Bonfanti, Matteo and Martinazzo, Rocco},
 doi = {10.1002/QUA.25192},
 journal = {International Journal of Quantum Chemistry},
 number = {21}
}

Elementary processes involving atomic and molecular species at surfaces are reviewed. The emphasis is on simple classical and quantum models that help to single out unifying dynamical themes and to identify the basic physical mechanisms that underlie the rich variety of phenomena of surface chemistry. Starting from an elementary description of the energy transfer between a gas-phase species and a surface—for both classical and quantum lattices—the key processes establishing the formation of an adsorbed phase (sticking, diffusion and vibrational relaxation) are discussed. This is instrumental for introducing the simplest chemical transformations involving adsorbed species and/or scattering of gas-phase molecules: Langmuir–Hinshelwood, Hot-Atom, and Eley–Rideal reactions forming complex molecules from elementary constituents, and dissociative chemisorption of molecules into smaller fragments. Applications are also provided illustrating the ideas developed along the way at work in real-world gas-surface problems.

@article{
 title = {Quantum dynamical investigation of the isotope effect in H2 formation on graphite at cold collision energies},
 type = {article},
 year = {2016},
 pages = {6607-6617},
 volume = {18},
 websites = {https://pubs.rsc.org/en/content/articlehtml/2016/cp/c5cp07272g,https://pubs.rsc.org/en/content/articlelanding/2016/cp/c5cp07272g},
 month = {2},
 publisher = {The Royal Society of Chemistry},
 day = {24},
 id = {7bf211da-7c93-3ee5-87b7-cef7eb3f8b27},
 created = {2022-06-10T13:23:20.923Z},
 accessed = {2022-06-10},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-10T13:28:11.814Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The Eley–Rideal abstraction of hydrogen atoms on graphitic surfaces at cold collision energies was investigated using a time-dependent wave packet method within the rigid-flat surface approximation, with a focus on hydrogen–deuterium isotopic substitutions. It is found that the marked isotope effect of collinear collisions disappears when the full dimensionality of the problem is taken into account, thereby suggesting that abstraction is less direct than commonly believed and proceeds through glancing rather than head-on collisions. In contrast, a clear isotope effect is observed for “hot-atom” formation, which appears to be strongly favored for heavy projectiles because of their higher density of physisorbed states. Overall, the dynamics is essentially classical and reasonably well described by quasi-classical trajectory methods at all but the lowest energies (≲10 meV). A comparison of the results obtained in the (substrate) adiabatic and diabatic limits suggests that the reaction is only marginally affected by the lattice dynamics, but highlights the importance of including energy dissipation processes in order to accurately describe the internal excitation of the product molecules.},
 bibtype = {article},
 author = {Pasquini, Marta and Bonfanti, Matteo and Martinazzo, Rocco},
 doi = {10.1039/C5CP07272G},
 journal = {Physical Chemistry Chemical Physics},
 number = {9}
}

The Eley–Rideal abstraction of hydrogen atoms on graphitic surfaces at cold collision energies was investigated using a time-dependent wave packet method within the rigid-flat surface approximation, with a focus on hydrogen–deuterium isotopic substitutions. It is found that the marked isotope effect of collinear collisions disappears when the full dimensionality of the problem is taken into account, thereby suggesting that abstraction is less direct than commonly believed and proceeds through glancing rather than head-on collisions. In contrast, a clear isotope effect is observed for “hot-atom” formation, which appears to be strongly favored for heavy projectiles because of their higher density of physisorbed states. Overall, the dynamics is essentially classical and reasonably well described by quasi-classical trajectory methods at all but the lowest energies (≲10 meV). A comparison of the results obtained in the (substrate) adiabatic and diabatic limits suggests that the reaction is only marginally affected by the lattice dynamics, but highlights the importance of including energy dissipation processes in order to accurately describe the internal excitation of the product molecules.

@article{
 title = {Hydrogen on silicene: like or unlike graphene?},
 type = {article},
 year = {2016},
 pages = {15654-15666},
 volume = {18},
 websites = {https://pubs.rsc.org/en/content/articlehtml/2016/cp/c6cp01491g,https://pubs.rsc.org/en/content/articlelanding/2016/cp/c6cp01491g},
 month = {6},
 publisher = {The Royal Society of Chemistry},
 day = {8},
 id = {7db712cb-a275-3663-b20a-95269b555eed},
 created = {2022-06-10T13:23:25.358Z},
 accessed = {2022-06-10},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-10T13:28:11.905Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Hydrogenation of free-standing silicene, the two-dimensional allotrope of silicon, is investigated in detail using first-principles methods and compared with the adsorption of H atoms on graphene. Similarly to graphene, chemisorption of a single H atom on silicene induces the formation of a semilocalized state around the adatom, a sharp peak in the density of states at the Fermi level which acts as a strong resonant scatterer for charge carriers. This state hosts an unpaired electron, the itinerant electron of the resonating valence bond picture which primarily resides on the “majority” sublattice and biases the reactivity towards specific lattice positions. Contrary to graphene, sticking of hydrogen atoms is barrierless, on both the pristine and the hydrogenated surface. As a consequence, hydrogen adsorption on silicene is expected to proceed randomly under typical laboratory conditions, and preferential binding to form balanced dimers (or clusters) only occurs when thermodynamic equilibrium conditions prevail. The absence of clustering can be experimentally confirmed using scanning tunneling microscopy techniques since simulated imaging shows that the investigated structures provide distinguishable features that should allow their easy identification, if present on the surface. Overall, our findings can be rationalized by the fact that in silicene π bonds are weaker and the lattice is softer than in graphene and suggest that in silicene adatoms may severely limit carrier mobility.},
 bibtype = {article},
 author = {Pizzochero, Michele and Bonfanti, Matteo and Martinazzo, Rocco},
 doi = {10.1039/C6CP01491G},
 journal = {Physical Chemistry Chemical Physics},
 number = {23}
}

Hydrogenation of free-standing silicene, the two-dimensional allotrope of silicon, is investigated in detail using first-principles methods and compared with the adsorption of H atoms on graphene. Similarly to graphene, chemisorption of a single H atom on silicene induces the formation of a semilocalized state around the adatom, a sharp peak in the density of states at the Fermi level which acts as a strong resonant scatterer for charge carriers. This state hosts an unpaired electron, the itinerant electron of the resonating valence bond picture which primarily resides on the “majority” sublattice and biases the reactivity towards specific lattice positions. Contrary to graphene, sticking of hydrogen atoms is barrierless, on both the pristine and the hydrogenated surface. As a consequence, hydrogen adsorption on silicene is expected to proceed randomly under typical laboratory conditions, and preferential binding to form balanced dimers (or clusters) only occurs when thermodynamic equilibrium conditions prevail. The absence of clustering can be experimentally confirmed using scanning tunneling microscopy techniques since simulated imaging shows that the investigated structures provide distinguishable features that should allow their easy identification, if present on the surface. Overall, our findings can be rationalized by the fact that in silicene π bonds are weaker and the lattice is softer than in graphene and suggest that in silicene adatoms may severely limit carrier mobility.

@article{
 title = {Hydrogen Recombination and Dimer Formation on Graphite from Ab Initio Molecular Dynamics Simulations},
 type = {article},
 year = {2016},
 pages = {5032-5040},
 volume = {120},
 websites = {https://pubs.acs.org/doi/full/10.1021/acs.jpca.5b12761},
 month = {7},
 publisher = {American Chemical Society},
 day = {14},
 id = {3554afff-c1c9-3154-b335-9c6e5b8285cf},
 created = {2022-06-10T13:23:28.430Z},
 accessed = {2022-06-10},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-10T13:28:12.011Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {We studied Eley-Rideal molecular hydrogen formation on graphite using ab initio molecular dynamics, in the energy range relevant for the chemistry of the interstellar medium and for terrestrial experiments employing cold plasma (0.02-1 eV). We found substantial projectile steering effects that prevent dimer formation at low energies, thereby ruling out any catalytic synthetic pathways that form hydrogen molecules. Ortho and para dimers do form efficiently thanks to preferential sticking, but only at energies that are too high to be relevant for the chemistry of the interstellar medium. Computed reaction cross sections and ro-vibrational product populations are in good agreement with available experimental data and capable of generating adsorbate configurations similar to those observed with scanning tunneling microscopy techniques.},
 bibtype = {article},
 author = {Casolo, S. and Tantardini, G. F. and Martinazzo, R.},
 doi = {10.1021/ACS.JPCA.5B12761/ASSET/IMAGES/LARGE/JP-2015-127619_0005.JPEG},
 journal = {Journal of Physical Chemistry A},
 number = {27}
}

We studied Eley-Rideal molecular hydrogen formation on graphite using ab initio molecular dynamics, in the energy range relevant for the chemistry of the interstellar medium and for terrestrial experiments employing cold plasma (0.02-1 eV). We found substantial projectile steering effects that prevent dimer formation at low energies, thereby ruling out any catalytic synthetic pathways that form hydrogen molecules. Ortho and para dimers do form efficiently thanks to preferential sticking, but only at energies that are too high to be relevant for the chemistry of the interstellar medium. Computed reaction cross sections and ro-vibrational product populations are in good agreement with available experimental data and capable of generating adsorbate configurations similar to those observed with scanning tunneling microscopy techniques.

@article{
 title = {Note: Caldeira-Leggett model describes dynamics of hydrogen atoms on graphene},
 type = {article},
 year = {2016},
 keywords = {chemisorption,graphene,hydrogen},
 pages = {126101},
 volume = {145},
 websites = {https://aip.scitation.org/doi/abs/10.1063/1.4963737},
 month = {9},
 publisher = {AIP Publishing LLCAIP Publishing},
 day = {28},
 id = {f73d2056-d921-383f-ac8f-4d598f94cbf3},
 created = {2022-06-10T13:25:34.371Z},
 accessed = {2022-06-10},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-10T13:28:11.894Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 bibtype = {article},
 author = {Gottwald, Fabian and Bonfanti, Matteo and Martinazzo, Rocco and Ivanov, Sergei D. and Kühn, Oliver},
 doi = {10.1063/1.4963737},
 journal = {The Journal of Chemical Physics},
 number = {12}
}

@article{
 title = {Exploiting the Photonic Crystal Properties of TiO2 Nanotube Arrays to Enhance Photocatalytic Hydrogen Production},
 type = {article},
 year = {2016},
 keywords = {TiO2 nanotubes,electrochemical anodization,photocatalytic water splitting,photoelectrochemical cell,photonic bandgap,photonic crystals},
 pages = {1345-1353},
 volume = {6},
 websites = {https://pubs.acs.org/doi/full/10.1021/acscatal.5b02817},
 month = {2},
 publisher = {American Chemical Society},
 day = {5},
 id = {0e9bbecc-4998-33e3-857e-abbb834eee44},
 created = {2022-06-10T13:25:36.835Z},
 accessed = {2022-06-10},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-10T13:28:12.103Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Two series of self-assembled TiO2 nanotube (NT) arrays were grown by electrochemical anodization on a metallic titanium substrate with different anodization times and applied potentials in HF-containing ethylene glycol electrolyte solutions and postcalcined at 450°C. The obtained thin films were characterized by FESEM, XRD, and UV-vis-NIR DRS analyses and tested as photoanodes in incident photon to current efficiency (IPCE) measurements and in a two-compartment photoelectrochemical cell (PEC) for separate H2 and O2 production. The photocatalytic performance of the NT arrays significantly increased with an increase in the potential applied during anodization (i.e., with increasing the NT inner diameter) and the incident angle of the light. IPCE measurements revealed that such unexpected behavior is due to a red shift of the activity threshold that allows harvesting and converting a larger portion of the solar spectrum. This phenomenon is ascribed to the parallel shift of the photonic band gap position originated by the intrinsic photonic crystal properties and demonstrates the important role played by ordered hierarchical structures in improving the photocatalytic performance of NT arrays by confining and manipulating light.},
 bibtype = {article},
 author = {Chiarello, Gian Luca and Zuliani, Alessio and Ceresoli, Davide and Martinazzo, Rocco and Selli, Elena},
 doi = {10.1021/ACSCATAL.5B02817/ASSET/IMAGES/LARGE/CS-2015-028173_0013.JPEG},
 journal = {ACS Catalysis},
 number = {2}
}

Two series of self-assembled TiO2 nanotube (NT) arrays were grown by electrochemical anodization on a metallic titanium substrate with different anodization times and applied potentials in HF-containing ethylene glycol electrolyte solutions and postcalcined at 450°C. The obtained thin films were characterized by FESEM, XRD, and UV-vis-NIR DRS analyses and tested as photoanodes in incident photon to current efficiency (IPCE) measurements and in a two-compartment photoelectrochemical cell (PEC) for separate H2 and O2 production. The photocatalytic performance of the NT arrays significantly increased with an increase in the potential applied during anodization (i.e., with increasing the NT inner diameter) and the incident angle of the light. IPCE measurements revealed that such unexpected behavior is due to a red shift of the activity threshold that allows harvesting and converting a larger portion of the solar spectrum. This phenomenon is ascribed to the parallel shift of the photonic band gap position originated by the intrinsic photonic crystal properties and demonstrates the important role played by ordered hierarchical structures in improving the photocatalytic performance of NT arrays by confining and manipulating light.

@article{
 title = {Inherently Chiral Spider-Like Oligothiophenes},
 type = {article},
 year = {2016},
 keywords = {chirality,enantiorecognition,hyperbranching,molecularly imprinted polymers,oligothiophenes},
 pages = {10839-10847},
 volume = {22},
 websites = {https://onlinelibrary.wiley.com/doi/full/10.1002/chem.201504899,https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.201504899,https://chemistry-europe.onlinelibrary.wiley.com/doi/full/10.1002/chem.201504899},
 month = {7},
 publisher = {John Wiley & Sons, Ltd},
 day = {25},
 id = {f07f368f-f508-3da3-9edc-277467441b6f},
 created = {2022-06-10T13:25:39.091Z},
 accessed = {2022-06-10},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-10T13:28:11.741Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The racemate of an inherently chiral “spider-like” octathiophene monomer T83, in which chirality is generated by torsion in its backbone, was synthesized. The racemate was resolved into configurationally stable antipodes by HPLC on a chiral stationary phase. Electrooxidation of the enantiomers resulted in materials displaying high enantiorecognition ability towards the antipodes of some chiral probes. Moreover, the T83racemate demonstrated great aptitude to stimulate formation of 3D rigid architectures if used as a cross-linking monomer for molecular imprinting. This feature was exploited to devise a molecularly imprinted polymer-based chemosensor selective for a thymine–adenine oligonucleotide.},
 bibtype = {article},
 author = {Sannicolò, Francesco and Mussini, Patrizia R. and Benincori, Tiziana and Martinazzo, Rocco and Arnaboldi, Serena and Appoloni, Giulio and Panigati, Monica and Quartapelle Procopio, Elsa and Marino, Valentina and Cirilli, Roberto and Casolo, Simone and Kutner, Wlodzimierz and Noworyta, Krzysztof and Pietrzyk-Le, Agnieszka and Iskierko, Zofia and Bartold, Katarzyna},
 doi = {10.1002/CHEM.201504899},
 journal = {Chemistry – A European Journal},
 number = {31}
}

The racemate of an inherently chiral “spider-like” octathiophene monomer T83, in which chirality is generated by torsion in its backbone, was synthesized. The racemate was resolved into configurationally stable antipodes by HPLC on a chiral stationary phase. Electrooxidation of the enantiomers resulted in materials displaying high enantiorecognition ability towards the antipodes of some chiral probes. Moreover, the T83racemate demonstrated great aptitude to stimulate formation of 3D rigid architectures if used as a cross-linking monomer for molecular imprinting. This feature was exploited to devise a molecularly imprinted polymer-based chemosensor selective for a thymine–adenine oligonucleotide.

@article{
 title = {Cover Picture: Inherently Chiral Spider-Like Oligothiophenes (Chem. Eur. J. 31/2016)},
 type = {article},
 year = {2016},
 keywords = {chirality,enantiorecognition,hyperbranching,molecularly imprinted polymers,oligothiophenes},
 pages = {10681-10681},
 volume = {22},
 websites = {https://onlinelibrary.wiley.com/doi/full/10.1002/chem.201602280,https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.201602280,https://chemistry-europe.onlinelibrary.wiley.com/doi/full/10.1002/chem.201602280},
 month = {7},
 publisher = {John Wiley & Sons, Ltd},
 day = {25},
 id = {8fc8fdd5-f0b3-327c-b0e8-f089cfd2dbdf},
 created = {2022-06-10T13:25:41.760Z},
 accessed = {2022-06-10},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-10T13:28:11.799Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 bibtype = {article},
 author = {Sannicolò, Francesco and Mussini, Patrizia R. and Benincori, Tiziana and Martinazzo, Rocco and Arnaboldi, Serena and Appoloni, Giulio and Panigati, Monica and Quartapelle Procopio, Elsa and Marino, Valentina and Cirilli, Roberto and Casolo, Simone and Kutner, Wlodzimierz and Noworyta, Krzysztof and Pietrzyk-Le, Agnieszka and Iskierko, Zofia and Bartold, Katarzyna},
 doi = {10.1002/CHEM.201602280},
 journal = {Chemistry – A European Journal},
 number = {31}
}

@article{
 title = {Electron transport in carbon wires in contact with Ag electrodes: a detailed first principles investigation},
 type = {article},
 year = {2015},
 pages = {18413-18425},
 volume = {17},
 websites = {https://pubs.rsc.org/en/content/articlehtml/2015/cp/c5cp02796a,https://pubs.rsc.org/en/content/articlelanding/2015/cp/c5cp02796a},
 month = {7},
 publisher = {The Royal Society of Chemistry},
 day = {8},
 id = {2293b206-f282-369b-8f36-e21b25bb6be4},
 created = {2022-06-10T13:36:08.771Z},
 accessed = {2022-06-10},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-10T13:41:14.431Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The structure and electronic properties of carbon atom chains Cn in contact with Ag electrodes are investigated in detail with first principles means. The ideal Ag(100) surface is used as a model for binding, and electron transport through the chains is studied as a function of their length, applied bias voltage, presence of capping atoms (Si, S) and adsorption site. It is found that the metal–molecule bond largely influences electronic coupling to the leads. Without capping atoms the quality of the electric contact improves when increasing the carbon atom coordination number to the metal (1, 2 and 4 for adsorption on a top, bridge and hollow position, respectively) and this finding translates almost unchanged in more realistic tip-like contacts which present one, two or four metal atoms at the contact. Current–voltage characteristics show Ohmic behaviour over a wide range of bias voltages and the resulting conductances change only weakly when increasing the wire length. The effect of a capping species is typically drastic, and either largely reduces (S) or largely increases (Si) the coupling of the wire to the electrodes. Comparison of our findings with recent experimental results highlights the limits of the adopted approach, which can be traced back to the known gap problem of density-functional-theory.},
 bibtype = {article},
 author = {Bonardi, Paolo and Achilli, Simona and Tantardini, Gian Franco and Martinazzo, Rocco},
 doi = {10.1039/C5CP02796A},
 journal = {Physical Chemistry Chemical Physics},
 number = {28}
}

The structure and electronic properties of carbon atom chains Cn in contact with Ag electrodes are investigated in detail with first principles means. The ideal Ag(100) surface is used as a model for binding, and electron transport through the chains is studied as a function of their length, applied bias voltage, presence of capping atoms (Si, S) and adsorption site. It is found that the metal–molecule bond largely influences electronic coupling to the leads. Without capping atoms the quality of the electric contact improves when increasing the carbon atom coordination number to the metal (1, 2 and 4 for adsorption on a top, bridge and hollow position, respectively) and this finding translates almost unchanged in more realistic tip-like contacts which present one, two or four metal atoms at the contact. Current–voltage characteristics show Ohmic behaviour over a wide range of bias voltages and the resulting conductances change only weakly when increasing the wire length. The effect of a capping species is typically drastic, and either largely reduces (S) or largely increases (Si) the coupling of the wire to the electrodes. Comparison of our findings with recent experimental results highlights the limits of the adopted approach, which can be traced back to the known gap problem of density-functional-theory.

@article{
 title = {Vibrational relaxation and decoherence in structured environments: a numerical investigation},
 type = {article},
 year = {2015},
 keywords = {Relaxation,brownian motion,quantum dynamics,spectral density},
 pages = {556-569},
 volume = {527},
 websites = {https://onlinelibrary.wiley.com/doi/full/10.1002/andp.201500144,https://onlinelibrary.wiley.com/doi/abs/10.1002/andp.201500144,https://onlinelibrary.wiley.com/doi/10.1002/andp.201500144},
 month = {10},
 publisher = {John Wiley & Sons, Ltd},
 day = {1},
 id = {d4fa14a9-0447-3976-8778-aab3837a4b93},
 created = {2022-06-10T13:36:11.261Z},
 accessed = {2022-06-10},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-10T13:41:14.541Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Vibrational relaxation is a key issue in chemical reaction dynamics in condensed phase and at the gas-surface interface, where the environment is typically highly structured and cannot be expressed in terms of a simple friction coefficient. Rather, full knowledge of the coupling of the molecular oscillator to the environment is required, as typically subsumed in the spectral density of the environmental coupling. Here, we focus on harmonic Brownian motion and investigate the effectiveness of classical, canonical position autocorrelation functions to compute the spectral density of the coupling needed to describe vibrational relaxation in complex environments. Classical dynamics is performed on model systems, and several effects are investigated in detail, notably the presence of anharmonicity, the role of a high-frequency "Debye" cutoff in the environment and the influence of the detailed structure of the latter. The spectral densities are then used in standard independent oscillator Hamiltonian models which are numerically solved at T = 0 K to investigate quantum relaxation and decoherence.},
 bibtype = {article},
 author = {Bonfanti, Matteo and Hughes, Keith H. and Burghardt, Irene and Martinazzo, Rocco},
 doi = {10.1002/ANDP.201500144},
 journal = {Annalen der Physik},
 number = {9-10}
}

Vibrational relaxation is a key issue in chemical reaction dynamics in condensed phase and at the gas-surface interface, where the environment is typically highly structured and cannot be expressed in terms of a simple friction coefficient. Rather, full knowledge of the coupling of the molecular oscillator to the environment is required, as typically subsumed in the spectral density of the environmental coupling. Here, we focus on harmonic Brownian motion and investigate the effectiveness of classical, canonical position autocorrelation functions to compute the spectral density of the coupling needed to describe vibrational relaxation in complex environments. Classical dynamics is performed on model systems, and several effects are investigated in detail, notably the presence of anharmonicity, the role of a high-frequency "Debye" cutoff in the environment and the influence of the detailed structure of the latter. The spectral densities are then used in standard independent oscillator Hamiltonian models which are numerically solved at T = 0 K to investigate quantum relaxation and decoherence.

@article{
 title = {Quantum dynamics of hydrogen atoms on graphene. I. System-bath modeling},
 type = {article},
 year = {2015},
 keywords = {SCF calculations,ab initio calculations,band structure,chemisorption,density functional theory,graphene,hydrogen,molecular dynamics method,potential energy surfaces},
 pages = {124703},
 volume = {143},
 websites = {https://aip.scitation.org/doi/abs/10.1063/1.4931116},
 month = {9},
 publisher = {AIP Publishing LLCAIP Publishing},
 day = {23},
 id = {44fbd9db-dfcc-3f3e-a00a-5f597982c3f9},
 created = {2022-06-10T13:36:13.416Z},
 accessed = {2022-06-10},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-10T13:41:14.880Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {An accurate system-bath model to investigate the quantum dynamics of hydrogen atoms chemisorbed on graphene is presented. The system comprises a hydrogen atom and the carbon atom from graphene that...},
 bibtype = {article},
 author = {Bonfanti, Matteo and Jackson, Bret and Hughes, Keith H. and Burghardt, Irene and Martinazzo, Rocco},
 doi = {10.1063/1.4931116},
 journal = {The Journal of Chemical Physics},
 number = {12}
}

An accurate system-bath model to investigate the quantum dynamics of hydrogen atoms chemisorbed on graphene is presented. The system comprises a hydrogen atom and the carbon atom from graphene that...

@article{
 title = {Quantum dynamics of hydrogen atoms on graphene. II. Sticking},
 type = {article},
 year = {2015},
 keywords = {chemisorption,graphene,hydrogen},
 pages = {124704},
 volume = {143},
 websites = {https://aip.scitation.org/doi/abs/10.1063/1.4931117},
 month = {9},
 publisher = {AIP Publishing LLCAIP Publishing},
 day = {23},
 id = {0767228c-db7a-32b9-9d8f-a4ae9fcd414e},
 created = {2022-06-10T13:36:15.567Z},
 accessed = {2022-06-10},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-10T13:41:14.371Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Following our recent system-bath modeling of the interaction between a hydrogen atom and a graphene surface [Bonfanti et al., J. Chem. Phys. 143, 124703 (2015)], we present the results of converged...},
 bibtype = {article},
 author = {Bonfanti, Matteo and Jackson, Bret and Hughes, Keith H. and Burghardt, Irene and Martinazzo, Rocco},
 doi = {10.1063/1.4931117},
 journal = {The Journal of Chemical Physics},
 number = {12}
}

Following our recent system-bath modeling of the interaction between a hydrogen atom and a graphene surface [Bonfanti et al., J. Chem. Phys. 143, 124703 (2015)], we present the results of converged...

@article{
 title = {Hydrogen adsorption on nitrogen and boron doped graphene},
 type = {article},
 year = {2015},
 keywords = {doping,first-principles,hydrogenation},
 pages = {425502},
 volume = {27},
 websites = {https://iopscience.iop.org/article/10.1088/0953-8984/27/42/425502,https://iopscience.iop.org/article/10.1088/0953-8984/27/42/425502/meta},
 month = {10},
 publisher = {IOP Publishing},
 day = {6},
 id = {a2ecacc3-f51b-3b11-9a22-0d180ae35c8a},
 created = {2022-06-10T13:36:17.899Z},
 accessed = {2022-06-10},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-10T13:41:14.563Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Hydrogen adsorption on boron and nitrogen doped graphene is investigated in detail by means of first-principles calculations. A comprehensive study is performed of the structural, electronic, and magnetic properties of chemisorbed hydrogen atoms and atom pairs near the dopant sites. The main effect of the substitutional atoms is charge doping which is found to greatly affect the adsorption process by increasing the binding energy at the sites closest to the substitutional species. It is also found that doping does not induce magnetism despite the odd number of electrons per atom introduced by the foreign species, and that it quenches the paramagnetic response of chemisorbed H atoms on graphene. Overall, the effects are similar for B and N doping, with only minor differences in the adsorption energetics due to different sizes of the dopant atoms and the accompanying lattice distortions.},
 bibtype = {article},
 author = {Pizzochero, Michele and Leenaerts, Ortwin and Partoens, Bart and Martinazzo, Rocco and Peeters, Fran�ois M.},
 doi = {10.1088/0953-8984/27/42/425502},
 journal = {Journal of Physics: Condensed Matter},
 number = {42}
}

Hydrogen adsorption on boron and nitrogen doped graphene is investigated in detail by means of first-principles calculations. A comprehensive study is performed of the structural, electronic, and magnetic properties of chemisorbed hydrogen atoms and atom pairs near the dopant sites. The main effect of the substitutional atoms is charge doping which is found to greatly affect the adsorption process by increasing the binding energy at the sites closest to the substitutional species. It is also found that doping does not induce magnetism despite the odd number of electrons per atom introduced by the foreign species, and that it quenches the paramagnetic response of chemisorbed H atoms on graphene. Overall, the effects are similar for B and N doping, with only minor differences in the adsorption energetics due to different sizes of the dopant atoms and the accompanying lattice distortions.

@article{
 title = {Structure and stability of hydrogenated carbon atom vacancies in graphene},
 type = {article},
 year = {2014},
 pages = {165-174},
 volume = {77},
 websites = {http://dx.doi.org/10.1016/j.carbon.2014.05.018},
 month = {10},
 publisher = {Pergamon},
 day = {1},
 id = {76a4027a-5c21-39a0-82b9-212e204ee4e5},
 created = {2022-06-15T17:51:25.921Z},
 accessed = {2022-06-15},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-15T18:17:42.659Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Adsorption of hydrogen atoms to a carbon atom vacancy in graphene is investigated by means of periodic first principles calculations, up to the fully hydrogenated state where six H atoms chemically bind to the vacancy. Addition of a single H atom is highly exothermic and barrierless, and binding energies remain substantial for further hydrogenation, with a preference towards structures with the least number of geminal pairs. Thermodynamic analysis shows that defective graphene is extremely sensitive to hydrogenation, with the triply hydrogenated anti-structure prevailing at room temperature and for a wide range of H2 partial pressures, from ∼1 bar down to <10 -20 bar. This structure has one unpaired electron and provides a spin-half local magnetic moment contribution to graphene paramagnetism. Comparison of our results with recent transmission electron microscopy, scanning tunneling microscopy and muon-spin-resonance experiments suggest that carbon atom vacancies may actually be hydrogenated to various degrees under varying conditions. © 2014 Elsevier Ltd. All rights reserved.},
 bibtype = {article},
 author = {Casartelli, Marina and Casolo, Simone and Tantardini, Gian Franco and Martinazzo, Rocco},
 doi = {10.1016/J.CARBON.2014.05.018},
 journal = {Carbon}
}

Adsorption of hydrogen atoms to a carbon atom vacancy in graphene is investigated by means of periodic first principles calculations, up to the fully hydrogenated state where six H atoms chemically bind to the vacancy. Addition of a single H atom is highly exothermic and barrierless, and binding energies remain substantial for further hydrogenation, with a preference towards structures with the least number of geminal pairs. Thermodynamic analysis shows that defective graphene is extremely sensitive to hydrogenation, with the triply hydrogenated anti-structure prevailing at room temperature and for a wide range of H2 partial pressures, from ∼1 bar down to <10 -20 bar. This structure has one unpaired electron and provides a spin-half local magnetic moment contribution to graphene paramagnetism. Comparison of our results with recent transmission electron microscopy, scanning tunneling microscopy and muon-spin-resonance experiments suggest that carbon atom vacancies may actually be hydrogenated to various degrees under varying conditions. © 2014 Elsevier Ltd. All rights reserved.

@article{
 title = {Non-Markovian reduced dynamics of ultrafast charge transfer at an oligothiophene–fullerene heterojunction},
 type = {article},
 year = {2014},
 keywords = {Exciton dynamics,HEOM,Non-Markovian,Organic photovoltaics,Spectral density},
 pages = {111-118},
 volume = {442},
 websites = {http://dx.doi.org/10.1016/j.chemphys.2014.06.015},
 month = {10},
 publisher = {North-Holland},
 day = {17},
 id = {344a105b-78f6-3f15-a38f-170c44570b3c},
 created = {2022-06-15T17:51:45.374Z},
 accessed = {2022-06-15},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-15T18:07:13.644Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {We extend our recent quantum dynamical study of the exciton dissociation and charge transfer at an oligothiophene-fullerene heterojunction interface (Tamura et al., 2012) [6] by investigating the process using the non-perturbative hierarchical equations of motion (HEOM) approach. Based upon an effective mode reconstruction of the spectral density the effect of temperature on the charge transfer is studied using reduced density matrices. It was found that the temperature had little effect on the charge transfer and a coherent dynamics persists over the first few tens of femtoseconds, indicating that the primary charge transfer step proceeds by an activationless pathway.},
 bibtype = {article},
 author = {Hughes, Keith H. and Cahier, Benjamin and Martinazzo, Rocco and Tamura, Hiroyuki and Burghardt, Irene},
 doi = {10.1016/J.CHEMPHYS.2014.06.015},
 journal = {Chemical Physics}
}

We extend our recent quantum dynamical study of the exciton dissociation and charge transfer at an oligothiophene-fullerene heterojunction interface (Tamura et al., 2012) [6] by investigating the process using the non-perturbative hierarchical equations of motion (HEOM) approach. Based upon an effective mode reconstruction of the spectral density the effect of temperature on the charge transfer is studied using reduced density matrices. It was found that the temperature had little effect on the charge transfer and a coherent dynamics persists over the first few tens of femtoseconds, indicating that the primary charge transfer step proceeds by an activationless pathway.

@article{
 title = {Structural and optical properties of inherently chiral polythiophenes: A combined CD-electrochemistry, circularly polarized luminescence, and TD-DFT investigation},
 type = {article},
 year = {2014},
 pages = {16019-16027},
 volume = {118},
 websites = {https://pubs.acs.org/doi/abs/10.1021/jp504307v},
 month = {7},
 publisher = {American Chemical Society},
 day = {24},
 id = {94997eaf-36e2-3208-9d6b-8b39a0351741},
 created = {2022-06-15T17:52:17.947Z},
 accessed = {2022-06-15},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-15T17:58:20.950Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Circular dichroism (CD) and ultraviolet absorption (UV) spectra of films obtained by electrochemical polymerization of inherently chiral 2,2′-bis(2,2′-bithiophene-5-yl)-3,3′-bithianaphthene (T4-BT2) are taken during electrochemical polarization cycles. Besides the bisignate CD features in the near UV range recorded at zero potential, new features in the visible-near-infrared range are observed under increased applied potential. Results are interpreted with the help of static and time-dependent (TD) density functional theory (DFT) calculations, which shed light on the structural and electronic properties of neutral and charged oligomers (from monomers to tetramers) and reproduce UV and CD spectra satisfactorily. Furthermore, properties of the excited state of T4-BT2 monomers in solution are enlightened by combining circularly polarized luminescence (CPL) measurements with TD-DFT calculations. © 2014 American Chemical Society.},
 bibtype = {article},
 author = {Longhi, Giovanna and Abbate, Sergio and Mazzeo, Giuseppe and Castiglioni, Ettore and Mussini, Patrizia and Benincori, Tiziana and Martinazzo, Rocco and Sannicolò, Francesco},
 doi = {10.1021/JP504307V/SUPPL_FILE/JP504307V_SI_001.PDF},
 journal = {Journal of Physical Chemistry C},
 number = {29}
}

Circular dichroism (CD) and ultraviolet absorption (UV) spectra of films obtained by electrochemical polymerization of inherently chiral 2,2′-bis(2,2′-bithiophene-5-yl)-3,3′-bithianaphthene (T4-BT2) are taken during electrochemical polarization cycles. Besides the bisignate CD features in the near UV range recorded at zero potential, new features in the visible-near-infrared range are observed under increased applied potential. Results are interpreted with the help of static and time-dependent (TD) density functional theory (DFT) calculations, which shed light on the structural and electronic properties of neutral and charged oligomers (from monomers to tetramers) and reproduce UV and CD spectra satisfactorily. Furthermore, properties of the excited state of T4-BT2 monomers in solution are enlightened by combining circularly polarized luminescence (CPL) measurements with TD-DFT calculations. © 2014 American Chemical Society.

@article{
 title = {Hydrogen-dimer lines and electron waveguides in graphene},
 type = {article},
 year = {2014},
 pages = {17610-17616},
 volume = {16},
 websites = {https://pubs.rsc.org/en/content/articlehtml/2014/cp/c4cp01025f,https://pubs.rsc.org/en/content/articlelanding/2014/cp/c4cp01025f},
 month = {7},
 publisher = {The Royal Society of Chemistry},
 day = {30},
 id = {a3a92c69-2ff2-309a-ad0b-f86f4c9d107b},
 created = {2022-06-15T17:54:43.081Z},
 accessed = {2022-06-15},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-15T17:58:20.903Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The electronic and transport properties of graphene ribbons sandwiched between hydrogen dimer lines, of the kind recently realized by Nilsson et al., Carbon, 2012, 50, 2052, are investigated with the help of first principles methods. It is found that such lines of hydrogen atoms block conduction between neighboring channels and effectively allow the confinement of graphene charge carriers, thereby opening the possibility of imprinting nano-circuits in graphene by controlled hydrogenation.},
 bibtype = {article},
 author = {Achilli, Simona and Tantardini, Gian Franco and Martinazzo, Rocco},
 doi = {10.1039/C4CP01025F},
 journal = {Physical Chemistry Chemical Physics},
 number = {33}
}

The electronic and transport properties of graphene ribbons sandwiched between hydrogen dimer lines, of the kind recently realized by Nilsson et al., Carbon, 2012, 50, 2052, are investigated with the help of first principles methods. It is found that such lines of hydrogen atoms block conduction between neighboring channels and effectively allow the confinement of graphene charge carriers, thereby opening the possibility of imprinting nano-circuits in graphene by controlled hydrogenation.

@article{
 title = {Adiabatic potential energy surfaces for the low-energy collisional dynamics of C+(2 P) ions with H2 molecules},
 type = {article},
 year = {2014},
 pages = {6595-6603},
 volume = {118},
 websites = {https://pubs.acs.org/doi/abs/10.1021/jp5031834},
 month = {8},
 publisher = {American Chemical Society},
 day = {21},
 id = {32a918d3-b2ca-39c5-ad6f-42ae93a2aad3},
 created = {2022-06-15T17:55:21.469Z},
 accessed = {2022-06-15},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-15T17:58:20.877Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The low-energy electronic states of the CH2+ molecular ion are investigated with multireference configuration interaction calculations based on complete active space self-consistent field reference wave functions using a large C(6s5p4d3f)/H(8s6p3d1f) basis set. The focus is on the three lowest-lying states describing formation and destruction of the astrophysically relevant methylidine cation CH+. Both processes are discussed in light of the topology of the relevant potential energy surfaces and their intersections. © 2014 American Chemical Society.},
 bibtype = {article},
 author = {Bonfanti, Matteo and Tantardini, Gian Franco and Martinazzo, Rocco},
 doi = {10.1021/JP5031834/ASSET/IMAGES/MEDIUM/JP-2014-031834_0011.GIF},
 journal = {Journal of Physical Chemistry A},
 number = {33}
}

The low-energy electronic states of the CH2+ molecular ion are investigated with multireference configuration interaction calculations based on complete active space self-consistent field reference wave functions using a large C(6s5p4d3f)/H(8s6p3d1f) basis set. The focus is on the three lowest-lying states describing formation and destruction of the astrophysically relevant methylidine cation CH+. Both processes are discussed in light of the topology of the relevant potential energy surfaces and their intersections. © 2014 American Chemical Society.

@article{
 title = {Inherently Chiral Macrocyclic Oligothiophenes: Easily Accessible Electrosensitive Cavities with Outstanding Enantioselection Performances},
 type = {article},
 year = {2014},
 keywords = {chirality,circularly polarized luminescence,enantioselectivity,macrocycles,oligothiophenes},
 pages = {15298-15302},
 volume = {20},
 websites = {https://onlinelibrary.wiley.com/doi/full/10.1002/chem.201404331,https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.201404331,https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.201404331},
 month = {11},
 publisher = {John Wiley & Sons, Ltd},
 day = {17},
 id = {ad3b7313-31f7-3d2e-b4e9-4362aed74a40},
 created = {2022-06-15T17:56:41.979Z},
 accessed = {2022-06-15},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-15T17:58:20.914Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Linear conjugated oligothiophenes of variable length and different substitution pattern are ubiquitous in technologically advanced optoelectronic devices, though limitations in application derive from insolubility, scarce processability and chain-end effects. This study describes an easy access to chiral cyclic oligothiophenes constituted by 12 and 18 fully conjugated thiophene units. Chemical oxidation of an "inherently chiral" sexithiophene monomer, synthesized in two steps from commercially available materials, induces the formation of an elliptical dimer and a triangular trimer endowed with electrosensitive cavities of different tunable sizes. Combination of chirality with electroactivity makes these molecules unique in the current oligothiophenes literature. These macrocycles, which are stable and soluble in most organic solvents, show outstanding chiroptical properties, high circularly polarized luminescence effects and an exceptional enantiorecognition ability.},
 bibtype = {article},
 author = {Sannicolò, Francesco and Mussini, Patrizia R. and Benincori, Tiziana and Cirilli, Roberto and Abbate, Sergio and Arnaboldi, Serena and Casolo, Simone and Castiglioni, Ettore and Longhi, Giovanna and Martinazzo, Rocco and Panigati, Monica and Pappini, Marco and Procopio, Elsa Quartapelle and Rizzo, Simona},
 doi = {10.1002/CHEM.201404331},
 journal = {Chemistry – A European Journal},
 number = {47}
}

Linear conjugated oligothiophenes of variable length and different substitution pattern are ubiquitous in technologically advanced optoelectronic devices, though limitations in application derive from insolubility, scarce processability and chain-end effects. This study describes an easy access to chiral cyclic oligothiophenes constituted by 12 and 18 fully conjugated thiophene units. Chemical oxidation of an "inherently chiral" sexithiophene monomer, synthesized in two steps from commercially available materials, induces the formation of an elliptical dimer and a triangular trimer endowed with electrosensitive cavities of different tunable sizes. Combination of chirality with electroactivity makes these molecules unique in the current oligothiophenes literature. These macrocycles, which are stable and soluble in most organic solvents, show outstanding chiroptical properties, high circularly polarized luminescence effects and an exceptional enantiorecognition ability.

@article{
 title = {Spin coupling around a carbon atom vacancy in graphene},
 type = {article},
 year = {2013},
 pages = {195424},
 volume = {88},
 websites = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.88.195424},
 month = {11},
 publisher = {American Physical Society},
 day = {22},
 id = {636c787f-b2f1-33af-aa84-3cdbc2fc7ecf},
 created = {2022-06-15T18:00:40.487Z},
 accessed = {2022-06-15},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-15T18:19:50.373Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {We investigate the details of the electronic structure in the neighborhoods of a carbon atom vacancy in graphene by employing magnetization-constrained density-functional theory on periodic slabs, and spin-exact, multireference, second-order perturbation theory on a finite cluster. The picture that emerges is that of two local magnetic moments (one π-like and one σ-like) decoupled from the π band and coupled to each other. We find that the ground state is a triplet with a planar equilibrium geometry where an apical C atom opposes a pentagonal ring. This state lies ∼0.2 eV lower in energy than the open-shell singlet with one spin flipped, which is a bistable system with two equivalent equilibrium lattice configurations (for the apical C atom above or below the lattice plane) and a barrier ∼0.1 eV high separating them. Accordingly, a bare carbon atom vacancy is predicted to be a spin-1 paramagnetic species, but spin-12 paramagnetism can be accommodated if binding to foreign species, ripples, coupling to a substrate, or doping are taken into account. © 2013 American Physical Society.},
 bibtype = {article},
 author = {Casartelli, M. and Casolo, S. and Tantardini, G. F. and Martinazzo, R.},
 doi = {10.1103/PHYSREVB.88.195424/FIGURES/7/MEDIUM},
 journal = {Physical Review B - Condensed Matter and Materials Physics},
 number = {19}
}

We investigate the details of the electronic structure in the neighborhoods of a carbon atom vacancy in graphene by employing magnetization-constrained density-functional theory on periodic slabs, and spin-exact, multireference, second-order perturbation theory on a finite cluster. The picture that emerges is that of two local magnetic moments (one π-like and one σ-like) decoupled from the π band and coupled to each other. We find that the ground state is a triplet with a planar equilibrium geometry where an apical C atom opposes a pentagonal ring. This state lies ∼0.2 eV lower in energy than the open-shell singlet with one spin flipped, which is a bistable system with two equivalent equilibrium lattice configurations (for the apical C atom above or below the lattice plane) and a barrier ∼0.1 eV high separating them. Accordingly, a bare carbon atom vacancy is predicted to be a spin-1 paramagnetic species, but spin-12 paramagnetism can be accommodated if binding to foreign species, ripples, coupling to a substrate, or doping are taken into account. © 2013 American Physical Society.

@article{
 title = {Insights into H2 formation in space from ab initio molecular dynamics},
 type = {article},
 year = {2013},
 keywords = {Density functional theory,Graphite-graphene,Hydrogen recombination,Interstellar chemistry},
 pages = {6674-6677},
 volume = {110},
 month = {4},
 publisher = {National Academy of Sciences},
 day = {23},
 id = {c4a26030-131b-3b3c-8a76-763688ecb10a},
 created = {2022-06-15T18:01:36.050Z},
 accessed = {2022-06-15},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-15T18:19:50.403Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Hydrogen formation is a key process for the physics and the chemistry of interstellar clouds. Molecular hydrogen is believed to form on the carbonaceous surface of dust grains, and several mechanisms have been invokedtoexplain its abundance indifferent regions of space, from cold interstellar clouds to warm photon-dominated regions. Here, we investigate direct (Eley-Rideal) recombination including lattice dynamics, surface corrugation, and competing H-dimers formation by means of ab initio molecular dynamics. We find that Eley-Rideal reaction dominates at energies relevant for the interstellar medium and alone may explain observations if the possibility of facile sticking at special sites (edges, point defects, etc.) on the surface of the dust grains is taken into account.},
 bibtype = {article},
 author = {Casolo, Simone and Tantardini, Gian Franco and Martinazzo, Rocco},
 doi = {10.1073/PNAS.1301433110/SUPPL_FILE/PNAS.201301433SI.PDF},
 journal = {Proceedings of the National Academy of Sciences of the United States of America},
 number = {17}
}

Hydrogen formation is a key process for the physics and the chemistry of interstellar clouds. Molecular hydrogen is believed to form on the carbonaceous surface of dust grains, and several mechanisms have been invokedtoexplain its abundance indifferent regions of space, from cold interstellar clouds to warm photon-dominated regions. Here, we investigate direct (Eley-Rideal) recombination including lattice dynamics, surface corrugation, and competing H-dimers formation by means of ab initio molecular dynamics. We find that Eley-Rideal reaction dominates at energies relevant for the interstellar medium and alone may explain observations if the possibility of facile sticking at special sites (edges, point defects, etc.) on the surface of the dust grains is taken into account.

@article{
 title = {Hydrogen Recombination on Graphitic Surfaces},
 type = {article},
 year = {2013},
 pages = {157-177},
 volume = {50},
 websites = {https://link.springer.com/chapter/10.1007/978-3-642-32955-5_7},
 id = {a7b57a30-ba76-36ab-a5b9-81f87121a385},
 created = {2022-06-15T18:04:10.123Z},
 accessed = {2022-06-15},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-16T07:34:22.940Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The detailed mechanisms behind the interaction of atomic hydrogen with graphitic surfaces and the formation of H2 molecules on these substrates have attracted much attention in the last decades because of their possible relevance in astrophysics, nuclear fusion, hydrogen storage and carbon-based nanotechnology. Here we summarize and critically analyze experimental and theoretical results within the field, with the aim of elucidating the complicated processes occurring in these systems. © Springer-Verlag Berlin Heidelberg 2013.},
 bibtype = {article},
 author = {Martinazzo, Rocco and Casolo, Simone and Hornekær, Liv H.},
 doi = {10.1007/978-3-642-32955-5_7},
 journal = {Springer Series in Surface Sciences}
}

The detailed mechanisms behind the interaction of atomic hydrogen with graphitic surfaces and the formation of H2 molecules on these substrates have attracted much attention in the last decades because of their possible relevance in astrophysics, nuclear fusion, hydrogen storage and carbon-based nanotechnology. Here we summarize and critically analyze experimental and theoretical results within the field, with the aim of elucidating the complicated processes occurring in these systems. © Springer-Verlag Berlin Heidelberg 2013.

@book{
 title = {A new wide band gap form of hydrogenated graphene},
 type = {book},
 year = {2012},
 source = {Carbon Nanostructures},
 keywords = {Dirac cone,Frenkel exciton,Graphene face,High symmetry point,Perturbation theory calculation},
 issue = {9783642206436},
 id = {9d224285-df57-3ebb-b48f-cc83762fb7f4},
 created = {2018-05-03T23:29:21.059Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:41.620Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {© 2012, Springer-Verlag Berlin Heidelberg. We propose a new form of partially hydrogenated graphene in which hydrogen atoms lay in para position to each other, forming a honeycomb-shaped superlattice. This arrangement is shown to be favored by progressive preferential sticking events, while its particular lattice symmetry guarantees the presence of a wide band gap. With the help of first principles DFT and many-body calculations we find this structure to be an insulator, similarly to graphane.},
 bibtype = {book},
 author = {Casolo, S. and Tantardini, G.F. and Martinazzo, R.},
 doi = {10.1007/978-3-642-20644-3_5}
}

© 2012, Springer-Verlag Berlin Heidelberg. We propose a new form of partially hydrogenated graphene in which hydrogen atoms lay in para position to each other, forming a honeycomb-shaped superlattice. This arrangement is shown to be favored by progressive preferential sticking events, while its particular lattice symmetry guarantees the presence of a wide band gap. With the help of first principles DFT and many-body calculations we find this structure to be an insulator, similarly to graphane.

@book{
 title = {The effect of atomic-scale defects on graphene electronic structure},
 type = {book},
 year = {2012},
 source = {Carbon Nanostructures},
 keywords = {Atom beam,Bipartite system,Dirac cone,Favoured configuration,Substitutional dopant},
 issue = {9783642206436},
 id = {303c771b-2f7d-3cd8-87db-12b174fed9da},
 created = {2018-05-04T01:57:35.050Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:41.109Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {© 2012, Springer-Verlag Berlin Heidelberg. Graphene, being one-atom thick, is extremely sensitive to the presence of adsorbed atoms and molecules and, more generally, to defects such as vacancies, holes and/or substitutional dopants. This feature, apart from being directly usable in molecular sensor devices, can also be employed to tune graphene electronic properties. Here we focus on those basic features of atomic-scale defects that can be useful for material design. Starting with isolated p z defects, we analyse the electronic structure of the defective substrate and how it determines the chemical reactivity towards adsorption (chemisorption) of atomic/molecular species. This is shown to produce non-random arrangement of adatoms on the surfaces. Then, we consider the reverse problem, that is how to use defects to engineer graphene electronic properties. In particular, we show that arranging defects to form honeycomb-shaped superlattices (what we may call “supergraphenes”) a sizeable gap opens in the band structure and new Dirac cones are created right close to the gap region. These possible structures might find important technological applications in the development of graphene-based logic transistors.},
 bibtype = {book},
 author = {Martinazzo, R. and Casolo, S. and Tantardini, G.F.},
 doi = {10.1007/978-3-642-20644-3_16}
}

© 2012, Springer-Verlag Berlin Heidelberg. Graphene, being one-atom thick, is extremely sensitive to the presence of adsorbed atoms and molecules and, more generally, to defects such as vacancies, holes and/or substitutional dopants. This feature, apart from being directly usable in molecular sensor devices, can also be employed to tune graphene electronic properties. Here we focus on those basic features of atomic-scale defects that can be useful for material design. Starting with isolated p z defects, we analyse the electronic structure of the defective substrate and how it determines the chemical reactivity towards adsorption (chemisorption) of atomic/molecular species. This is shown to produce non-random arrangement of adatoms on the surfaces. Then, we consider the reverse problem, that is how to use defects to engineer graphene electronic properties. In particular, we show that arranging defects to form honeycomb-shaped superlattices (what we may call “supergraphenes”) a sizeable gap opens in the band structure and new Dirac cones are created right close to the gap region. These possible structures might find important technological applications in the development of graphene-based logic transistors.

@article{
 title = {Non-Markovian reduced dynamics based upon a hierarchical effective-mode representation},
 type = {article},
 year = {2012},
 keywords = {Brownian motion,Fourier transforms,Laplace transforms,boson systems,harmonic oscillators,higher order statistics,master equation,mathematical operators},
 pages = {144107},
 volume = {137},
 websites = {https://aip.scitation.org/doi/abs/10.1063/1.4752078},
 month = {10},
 publisher = {American Institute of PhysicsAIP},
 day = {12},
 id = {c9b096ca-0534-3662-9f02-1fd2c5befbc8},
 created = {2022-06-16T07:32:38.595Z},
 accessed = {2022-06-16},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-16T07:35:50.528Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {false},
 hidden = {false},
 private_publication = {false},
 abstract = {A reduced dynamics representation is introduced which is tailored to a hierarchical, Mori-chain type representation of a bath of harmonic oscillators which are linearly coupled to a subsystem. We c...},
 bibtype = {article},
 author = {Burghardt, Irene and Martinazzo, Rocco and Hughes, Keith H.},
 doi = {10.1063/1.4752078},
 journal = {The Journal of Chemical Physics},
 number = {14}
}

A reduced dynamics representation is introduced which is tailored to a hierarchical, Mori-chain type representation of a bath of harmonic oscillators which are linearly coupled to a subsystem. We c...

@article{
 title = {Quantum dynamics of ultrafast charge transfer at an oligothiophene-fullerene heterojunction},
 type = {article},
 year = {2012},
 keywords = {band structure,charge transfer states,electron-phonon interactions,fullerenes,interface phonons,organic compounds,vibronic states},
 pages = {22A540},
 volume = {137},
 websites = {https://aip.scitation.org/doi/abs/10.1063/1.4751486},
 month = {9},
 publisher = {American Institute of PhysicsAIP},
 day = {19},
 id = {c38f7d2d-e96a-393b-8a4e-5dfdb1c16c63},
 created = {2022-06-16T07:33:02.708Z},
 accessed = {2022-06-16},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-16T07:35:50.405Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {false},
 hidden = {false},
 private_publication = {false},
 abstract = {Following up on our recent study of ultrafast charge separation at oligothiophene-fullerene interfaces [H. Tamura, I. Burghardt, and M. Tsukada, J. Phys. Chem. C 115, 10205 (2011)10.1021/jp203174e]...},
 bibtype = {article},
 author = {Tamura, Hiroyuki and Martinazzo, Rocco and Ruckenbauer, Matthias and Burghardt, Irene},
 doi = {10.1063/1.4751486},
 journal = {The Journal of Chemical Physics},
 number = {22}
}

Following up on our recent study of ultrafast charge separation at oligothiophene-fullerene interfaces [H. Tamura, I. Burghardt, and M. Tsukada, J. Phys. Chem. C 115, 10205 (2011)10.1021/jp203174e]...

@article{
 title = {Compact MCTDH wave functions for high-dimensional system-bath quantum dynamics},
 type = {article},
 year = {2012},
 pages = {11406-11413},
 volume = {116},
 websites = {https://pubs.acs.org/doi/full/10.1021/jp3064504},
 month = {11},
 publisher = {American Chemical Society},
 day = {26},
 id = {60984fd8-c115-34e9-897a-d7c918c4f297},
 created = {2022-06-16T07:33:27.728Z},
 accessed = {2022-06-16},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-16T07:35:50.427Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {false},
 hidden = {false},
 private_publication = {false},
 abstract = {We employ a simple multiconfiguration time-dependent Hartree (MCTDH) ansatz tailored to an effective-mode transformation of environmental variables that brings the bath into a linear chain form. In this form, important (primary) degrees of freedom can be easily identified and treated at a high correlation level, whereas secondary modes are left uncorrelated. The resulting approach scales linearly with the bath dimensions and allows us to easily access recurrence times much longer than usually possible, at a very small computational cost. Test calculations for model atom-surface problems show that the system dynamics is correctly reproduced in the relevant time window, and quantitative agreement is attained for energy relaxation and sticking, particularly in non-Markovian environments. These results pave the way for tackling realistic system-bath quantum dynamical problems on the picosecond scale. © 2012 American Chemical Society.},
 bibtype = {article},
 author = {Bonfanti, M. and Tantardini, G. F. and Hughes, K. H. and Martinazzo, R. and Burghardt, I.},
 doi = {10.1021/JP3064504/ASSET/IMAGES/LARGE/JP-2012-064504_0007.JPEG},
 journal = {Journal of Physical Chemistry A},
 number = {46}
}

We employ a simple multiconfiguration time-dependent Hartree (MCTDH) ansatz tailored to an effective-mode transformation of environmental variables that brings the bath into a linear chain form. In this form, important (primary) degrees of freedom can be easily identified and treated at a high correlation level, whereas secondary modes are left uncorrelated. The resulting approach scales linearly with the bath dimensions and allows us to easily access recurrence times much longer than usually possible, at a very small computational cost. Test calculations for model atom-surface problems show that the system dynamics is correctly reproduced in the relevant time window, and quantitative agreement is attained for energy relaxation and sticking, particularly in non-Markovian environments. These results pave the way for tackling realistic system-bath quantum dynamical problems on the picosecond scale. © 2012 American Chemical Society.

@article{
 title = {Reduced and exact quantum dynamics of the vibrational relaxation of a molecular system interacting with a finite-dimensional bath},
 type = {article},
 year = {2012},
 pages = {11118-11127},
 volume = {116},
 websites = {https://pubs.acs.org/doi/full/10.1021/jp304466u},
 month = {11},
 publisher = {American Chemical Society},
 day = {26},
 id = {0a09621f-3d06-3833-92f2-bad99e1ebe07},
 created = {2022-06-16T07:33:52.198Z},
 accessed = {2022-06-16},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-16T07:35:50.576Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {false},
 hidden = {false},
 private_publication = {false},
 abstract = {We investigate the vibrational relaxation of a Morse oscillator, nonlinearly coupled to a finite-dimensional bath of harmonic oscillators at zero temperature, using two different approaches: Reduced dynamics with the help of the Lindblad formalism of reduced density matrix theory in combination with Fermi's Golden Rule, and exact dynamics (within the chosen model) with the multiconfiguration time-dependent Hartree (MCTDH) method. Two different models have been constructed, the situation where the bath spectrum is exactly resonant with the anharmonic oscillator transition frequencies, and the case for which the subsystem is slightly off-resonant with the environment. At short times, reduced dynamics calculations describe the relaxation process qualitatively well but fail to reproduce recurrences observed with MCTDH for longer times. Lifetimes of all the vibrational levels of the Morse oscillator have been calculated, and both Lindblad and MCTDH results show the same dependence of the lifetimes on the initial vibrational state quantum number. A prediction, which should be generic for adsorbate systems is a striking, sharp increase of lifetimes of the subsystem vibrational levels close to the dissociation limit. This is contradictory with harmonic/linear extrapolation laws, which predict a monotonic decrease of the lifetime with initial vibrational quantum number. © 2012 American Chemical Society.},
 bibtype = {article},
 author = {Bouakline, Foudhil and Lüder, Franziska and Martinazzo, Rocco and Saalfrank, Peter},
 doi = {10.1021/JP304466U/ASSET/IMAGES/LARGE/JP-2012-04466U_0002.JPEG},
 journal = {Journal of Physical Chemistry A},
 number = {46}
}

We investigate the vibrational relaxation of a Morse oscillator, nonlinearly coupled to a finite-dimensional bath of harmonic oscillators at zero temperature, using two different approaches: Reduced dynamics with the help of the Lindblad formalism of reduced density matrix theory in combination with Fermi's Golden Rule, and exact dynamics (within the chosen model) with the multiconfiguration time-dependent Hartree (MCTDH) method. Two different models have been constructed, the situation where the bath spectrum is exactly resonant with the anharmonic oscillator transition frequencies, and the case for which the subsystem is slightly off-resonant with the environment. At short times, reduced dynamics calculations describe the relaxation process qualitatively well but fail to reproduce recurrences observed with MCTDH for longer times. Lifetimes of all the vibrational levels of the Morse oscillator have been calculated, and both Lindblad and MCTDH results show the same dependence of the lifetimes on the initial vibrational state quantum number. A prediction, which should be generic for adsorbate systems is a striking, sharp increase of lifetimes of the subsystem vibrational levels close to the dissociation limit. This is contradictory with harmonic/linear extrapolation laws, which predict a monotonic decrease of the lifetime with initial vibrational quantum number. © 2012 American Chemical Society.

@article{
 title = {A few simple rules governing hydrogenation of graphene dots},
 type = {article},
 year = {2011},
 keywords = {adsorption,binding energy,density functional theory,graphene,hydrogenation,tight-binding calculations},
 pages = {164701},
 volume = {135},
 websites = {https://aip.scitation.org/doi/abs/10.1063/1.3650693},
 month = {10},
 publisher = {American Institute of PhysicsAIP},
 day = {24},
 id = {999d5735-f275-3b76-8e69-2eb31df1cb2e},
 created = {2022-06-16T07:36:58.022Z},
 accessed = {2022-06-16},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-16T08:03:38.535Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {false},
 hidden = {false},
 private_publication = {false},
 abstract = {We investigated binding of hydrogen atoms to small polycyclic aromatic hydrocarbons (PAHs)—i.e., graphene dots with hydrogen-terminated edges—using density functional theory and correlated wavefunc...},
 bibtype = {article},
 author = {Bonfanti, M. and Casolo, S. and Tantardini, G. F. and Ponti, A. and Martinazzo, R.},
 doi = {10.1063/1.3650693},
 journal = {The Journal of Chemical Physics},
 number = {16}
}

We investigated binding of hydrogen atoms to small polycyclic aromatic hydrocarbons (PAHs)—i.e., graphene dots with hydrogen-terminated edges—using density functional theory and correlated wavefunc...

@article{
 title = {Unraveling a Brownian particle’s memory with effective mode chains},
 type = {article},
 year = {2011},
 pages = {030102},
 volume = {84},
 websites = {https://journals.aps.org/pre/abstract/10.1103/PhysRevE.84.030102},
 month = {9},
 publisher = {American Physical Society},
 day = {14},
 id = {1ca2754d-c3cd-3d6b-b4b1-52fe9ea961d9},
 created = {2022-06-16T07:43:19.656Z},
 accessed = {2022-06-16},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-16T08:03:38.351Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {false},
 hidden = {false},
 private_publication = {false},
 abstract = {Memory effects in quantum dynamical processes involving structured environments are presently difficult, if not impossible, to investigate using standard approaches. Progress can be made by transforming the environmental variables to a suitable chain representation which effectively performs a Markovian embedding of the dynamics. Here, we show that this effective-mode chain representation provides a unique way of unraveling the memory kernel κ(t) as a function of time. Truncated or Markov-closed chains with n effective modes exactly reproduce κ(t) to the 4nth order in time, up to an irrelevant constant of order κ(0)/n. These favorable convergence properties pave the way for efficient quantum simulations of fast (non-Markovian) processes by reduced dynamical models. © 2011 American Physical Society.},
 bibtype = {article},
 author = {Martinazzo, R. and Hughes, K. H. and Burghardt, I.},
 doi = {10.1103/PhysRevE.84.030102},
 journal = {Physical Review E},
 number = {3}
}

Memory effects in quantum dynamical processes involving structured environments are presently difficult, if not impossible, to investigate using standard approaches. Progress can be made by transforming the environmental variables to a suitable chain representation which effectively performs a Markovian embedding of the dynamics. Here, we show that this effective-mode chain representation provides a unique way of unraveling the memory kernel κ(t) as a function of time. Truncated or Markov-closed chains with n effective modes exactly reproduce κ(t) to the 4nth order in time, up to an irrelevant constant of order κ(0)/n. These favorable convergence properties pave the way for efficient quantum simulations of fast (non-Markovian) processes by reduced dynamical models. © 2011 American Physical Society.

@article{
 title = {Surface models and reaction barrier in Eley–Rideal formation of H2 on graphitic surfaces},
 type = {article},
 year = {2011},
 pages = {16680-16688},
 volume = {13},
 websites = {https://pubs.rsc.org/en/content/articlehtml/2011/cp/c1cp21900f,https://pubs.rsc.org/en/content/articlelanding/2011/cp/c1cp21900f},
 month = {9},
 publisher = {The Royal Society of Chemistry},
 day = {6},
 id = {5e49663f-fe45-3345-ae5a-d3945deaa824},
 created = {2022-06-16T07:44:42.219Z},
 accessed = {2022-06-16},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-16T08:03:38.564Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {false},
 hidden = {false},
 private_publication = {false},
 abstract = {The exothermic, collinearly-dominated Eley–Rideal hydrogen formation on graphite is studied with electronic structure and quantum dynamical means. In particular, the focus is on the importance of the model used to describe the graphitic substrate, in light of the marked discrepancies present in available literature results. To this end, the collinear reaction is considered and the potential energy surface is computed for a number of different graphitic surface models using Density Functional Theory (DFT) for different dynamical regimes. Quantum dynamics is performed with wavepacket techniques down to the cold collision energies relevant for the chemistry of the interstellar medium. Results show that the reactivity at moderate-to-high collision energies sensitively depends on the shape of the PES in the entrance channel, which in turn is related to the adopted surface model. At low energies we rule out the presence of any barrier to reaction, thereby highlighting the importance of quantum reflection in limiting the reaction efficiency.},
 bibtype = {article},
 author = {Bonfanti, Matteo and Casolo, Simone and Tantardini, Gian Franco and Martinazzo, Rocco},
 doi = {10.1039/C1CP21900F},
 journal = {Physical Chemistry Chemical Physics},
 number = {37}
}

The exothermic, collinearly-dominated Eley–Rideal hydrogen formation on graphite is studied with electronic structure and quantum dynamical means. In particular, the focus is on the importance of the model used to describe the graphitic substrate, in light of the marked discrepancies present in available literature results. To this end, the collinear reaction is considered and the potential energy surface is computed for a number of different graphitic surface models using Density Functional Theory (DFT) for different dynamical regimes. Quantum dynamics is performed with wavepacket techniques down to the cold collision energies relevant for the chemistry of the interstellar medium. Results show that the reactivity at moderate-to-high collision energies sensitively depends on the shape of the PES in the entrance channel, which in turn is related to the adopted surface model. At low energies we rule out the presence of any barrier to reaction, thereby highlighting the importance of quantum reflection in limiting the reaction efficiency.

@article{
 title = {The Effect of Atomic-Scale Defects and Dopants on Graphene Electronic Structure},
 type = {article},
 year = {2011},
 websites = {undefined/state.item.id},
 month = {3},
 publisher = {IntechOpen},
 day = {22},
 id = {c0083758-a5b9-37ba-978e-029fa81b8540},
 created = {2022-06-16T07:46:01.109Z},
 accessed = {2022-06-16},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-16T08:03:38.488Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {false},
 hidden = {false},
 private_publication = {false},
 abstract = {Graphene, being one-atom thick, is extremely sensitive to the presence of adsorbed atoms and molecules and, more generally, to defects such as vacancies, holes and/or substitutional dopants. This property, apart from being directly usable in molecular sensor devices, can also be employed to tune graphene electronic properties. Here we briefly review the basic features of atomic-scale defects that can be useful for material design. After a brief introduction on isolated $p_z$ defects, we analyse the electronic structure of multiple defective graphene substrates, and show how to predict the presence of microscopically ordered magnetic structures. Subsequently, we analyse the more complicated situation where the electronic structure, as modified by the presence of some defects, affects chemical reactivity of the substrate towards adsorption (chemisorption) of atomic/molecular species, leading to preferential sticking on specific lattice positions. Then, we consider the reverse problem, that is how to use defects to engineer graphene electronic properties. In this context, we show that arranging defects to form honeycomb-shaped superlattices (what we may call "supergraphenes") a sizeable gap opens in the band structure and new Dirac cones are created right close to the gapped region. Similarly, we show that substitutional dopants such as group IIIA/VA elements may have gapped quasi-conical structures corresponding to massive Dirac carriers. All these possible structures might find important technological applications in the development of graphene-based logic transistors.},
 bibtype = {article},
 author = {Martinazzo, Rocco and Casolo, Simone and Tantardini, Gian Franco},
 doi = {10.5772/14118},
 journal = {Physics and Applications of Graphene - Theory}
}

Graphene, being one-atom thick, is extremely sensitive to the presence of adsorbed atoms and molecules and, more generally, to defects such as vacancies, holes and/or substitutional dopants. This property, apart from being directly usable in molecular sensor devices, can also be employed to tune graphene electronic properties. Here we briefly review the basic features of atomic-scale defects that can be useful for material design. After a brief introduction on isolated $p_z$ defects, we analyse the electronic structure of multiple defective graphene substrates, and show how to predict the presence of microscopically ordered magnetic structures. Subsequently, we analyse the more complicated situation where the electronic structure, as modified by the presence of some defects, affects chemical reactivity of the substrate towards adsorption (chemisorption) of atomic/molecular species, leading to preferential sticking on specific lattice positions. Then, we consider the reverse problem, that is how to use defects to engineer graphene electronic properties. In this context, we show that arranging defects to form honeycomb-shaped superlattices (what we may call "supergraphenes") a sizeable gap opens in the band structure and new Dirac cones are created right close to the gapped region. Similarly, we show that substitutional dopants such as group IIIA/VA elements may have gapped quasi-conical structures corresponding to massive Dirac carriers. All these possible structures might find important technological applications in the development of graphene-based logic transistors.

@article{
 title = {Band engineering in graphene with superlattices of substitutional defects},
 type = {article},
 year = {2011},
 pages = {3250-3256},
 volume = {115},
 websites = {https://pubs.acs.org/doi/full/10.1021/jp109741s},
 month = {3},
 publisher = {American Chemical Society},
 day = {3},
 id = {8e492a9d-1f89-3a9d-ba6d-39c1da6bbecf},
 created = {2022-06-16T07:47:14.509Z},
 accessed = {2022-06-16},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-16T08:03:38.693Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {false},
 hidden = {false},
 private_publication = {false},
 abstract = {We investigate graphene superlattices of nitrogen and boron substitutional defects. Using symmetry arguments and electronic structure calculations we show how such superlattices can be used to modify graphene band structure. Specifically, depending on the superlattice symmetry, the structures considered here can either preserve the Dirac cones (D6h superlattices) or open a band gap (D3h). Relevant band parameters (carrier effective masses, group velocities, and gaps, when present) are found to depend on the superlattice constant n as 1/np where p is in the range 1-2, depending on the case considered. Overall, the results presented here show how one can tune the graphene band structure to a great extent by modifying a few superlattice parameters. © 2011 American Chemical Society.},
 bibtype = {article},
 author = {Casolo, S. and Martinazzo, R. and Tantardini, G. F.},
 doi = {10.1021/JP109741S/SUPPL_FILE/JP109741S_SI_001.PDF},
 journal = {Journal of Physical Chemistry C},
 number = {8}
}

We investigate graphene superlattices of nitrogen and boron substitutional defects. Using symmetry arguments and electronic structure calculations we show how such superlattices can be used to modify graphene band structure. Specifically, depending on the superlattice symmetry, the structures considered here can either preserve the Dirac cones (D6h superlattices) or open a band gap (D3h). Relevant band parameters (carrier effective masses, group velocities, and gaps, when present) are found to depend on the superlattice constant n as 1/np where p is in the range 1-2, depending on the case considered. Overall, the results presented here show how one can tune the graphene band structure to a great extent by modifying a few superlattice parameters. © 2011 American Chemical Society.

@article{
 title = {Benchmark calculations for dissipative dynamics of a system coupled to an anharmonic bath with the multiconfiguration time-dependent Hartree method},
 type = {article},
 year = {2011},
 keywords = {harmonic oscillators,quantum theory},
 pages = {094102},
 volume = {134},
 websites = {https://aip.scitation.org/doi/abs/10.1063/1.3556940},
 month = {3},
 publisher = {American Institute of PhysicsAIP},
 day = {1},
 id = {ad760d44-2efd-30b5-aaa8-10fb9e9c2869},
 created = {2022-06-16T07:49:05.950Z},
 accessed = {2022-06-16},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-16T08:03:38.210Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {false},
 hidden = {false},
 private_publication = {false},
 abstract = {In this paper, we present benchmark results for dissipative dynamics of a harmonic oscillator coupled to an anharmonic bath of Morse oscillators. The microscopic Hamiltonian has been chosen so that...},
 bibtype = {article},
 author = {Lpez-Lpez, S. and Martinazzo, R. and Nest, M.},
 doi = {10.1063/1.3556940},
 journal = {The Journal of Chemical Physics},
 number = {9}
}

In this paper, we present benchmark results for dissipative dynamics of a harmonic oscillator coupled to an anharmonic bath of Morse oscillators. The microscopic Hamiltonian has been chosen so that...

@article{
 title = {Communication: Universal Markovian reduction of Brownian particle dynamics},
 type = {article},
 year = {2011},
 keywords = {Brownian motion,Markov processes,differential equations},
 pages = {011101},
 volume = {134},
 websites = {https://aip.scitation.org/doi/abs/10.1063/1.3532408},
 month = {1},
 publisher = {American Institute of PhysicsAIP},
 day = {3},
 id = {095d79f2-df1f-3e99-96b8-4551937cf82f},
 created = {2022-06-16T07:52:44.385Z},
 accessed = {2022-06-16},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-16T08:03:38.224Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {false},
 hidden = {false},
 private_publication = {false},
 abstract = {Non-Markovian processes can often be turned Markovian by enlarging the set of variables. Here we show, by an explicit construction, how this can be done for the dynamics of a Brownian particle obey...},
 bibtype = {article},
 author = {Martinazzo, R. and Vacchini, B. and Hughes, K. H. and Burghardt, I.},
 doi = {10.1063/1.3532408},
 journal = {The Journal of Chemical Physics},
 number = {1}
}

Non-Markovian processes can often be turned Markovian by enlarging the set of variables. Here we show, by an explicit construction, how this can be done for the dynamics of a Brownian particle obey...

@article{
 title = {Generalized CC-TDSCF and LCSA: The system-energy representation},
 type = {article},
 year = {2011},
 keywords = {Hilbert spaces,SCF calculations,eigenvalues and eigenfunctions,wave functions},
 pages = {014102},
 volume = {134},
 websites = {https://aip.scitation.org/doi/abs/10.1063/1.3518418},
 month = {1},
 publisher = {American Institute of PhysicsAIP},
 day = {5},
 id = {d8aaf220-4914-3948-b38b-ffd6b6fa2c61},
 created = {2022-06-16T07:58:34.149Z},
 accessed = {2022-06-16},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-16T08:03:38.778Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {false},
 hidden = {false},
 private_publication = {false},
 abstract = {Typical (sub)system-bath quantum dynamical problems are often investigated by means of (approximate) reduced equations of motion. Wavepacket approaches to the dynamics of the whole system have gain...},
 bibtype = {article},
 author = {López-López, Sergio and Nest, Mathias and Martinazzo, Rocco},
 doi = {10.1063/1.3518418},
 journal = {The Journal of Chemical Physics},
 number = {1}
}

Typical (sub)system-bath quantum dynamical problems are often investigated by means of (approximate) reduced equations of motion. Wavepacket approaches to the dynamics of the whole system have gain...

@article{
 title = {Nano-technology, theoretical chemistry and computational chemistry},
 type = {article},
 year = {2010},
 volume = {9},
 id = {ccbb755d-ec1b-313a-8e06-2a9823f2b685},
 created = {2018-01-15T12:23:03.423Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:42.396Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 bibtype = {article},
 author = {Tantardini, G.F. and Martinazzo, R. and Casolo, S.},
 journal = {Mondo Digitale},
 number = {3}
}

@article{
 title = {Effective spectral densities for system-environment dynamics at conical intersections: S2–S1 conical intersection in pyrazine},
 type = {article},
 year = {2010},
 keywords = {Conical intersections,Quantum dynamics,Spectral density,System-bath dynamics},
 pages = {21-29},
 volume = {377},
 month = {11},
 publisher = {North-Holland},
 day = {25},
 id = {b08c890c-5fe9-39b7-9aad-35d46b4bdd5a},
 created = {2022-06-16T07:59:42.542Z},
 accessed = {2022-06-16},
 file_attached = {true},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-16T08:03:38.357Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {false},
 hidden = {false},
 private_publication = {false},
 abstract = {A recently developed effective-mode representation is employed to characterize the influence of a multi-dimensional environment on the S 2-S1 conical intersection in pyrazine, taken as a paradigm case of high-dimensional dynamics at a conical intersection. We consider a simplified model by which four modes are strongly coupled to the electronic subsystem while a number of weakly coupled tuning modes, inducing energy gap fluctuations, are sampled from a spectral density. The latter is approximated by a series of simplified spectral densities which can be cast into a continued-fraction form, as previously demonstrated in Hughes et al. (K.H. Hughes, C.D. Christ, I. Burghardt, J. Chem. Phys. 131 (2009) 124108). In the time domain, the hierarchy of spectral densities translates to truncated effective-mode chains with a Markovian or quasi-Markovian (Rubin type) closure. A sequential deconvolution procedure is employed to generate this chain representation. The implications for the ultrafast dynamics and its representation in terms of reduced-dimensional models are discussed. © 2010 Elsevier B.V. All rights reserved.},
 bibtype = {article},
 author = {Martinazzo, Rocco and Hughes, Keith H. and Martelli, Fausto and Burghardt, Irene},
 doi = {10.1016/J.CHEMPHYS.2010.08.010},
 journal = {Chemical Physics},
 number = {1-3}
}

A recently developed effective-mode representation is employed to characterize the influence of a multi-dimensional environment on the S 2-S1 conical intersection in pyrazine, taken as a paradigm case of high-dimensional dynamics at a conical intersection. We consider a simplified model by which four modes are strongly coupled to the electronic subsystem while a number of weakly coupled tuning modes, inducing energy gap fluctuations, are sampled from a spectral density. The latter is approximated by a series of simplified spectral densities which can be cast into a continued-fraction form, as previously demonstrated in Hughes et al. (K.H. Hughes, C.D. Christ, I. Burghardt, J. Chem. Phys. 131 (2009) 124108). In the time domain, the hierarchy of spectral densities translates to truncated effective-mode chains with a Markovian or quasi-Markovian (Rubin type) closure. A sequential deconvolution procedure is employed to generate this chain representation. The implications for the ultrafast dynamics and its representation in terms of reduced-dimensional models are discussed. © 2010 Elsevier B.V. All rights reserved.

@article{
 title = {Understanding adsorption of hydrogen atoms on graphene},
 type = {article},
 year = {2009},
 volume = {130},
 id = {444b403c-786b-3fa3-87a4-e5555851af8d},
 created = {2018-01-15T12:23:03.496Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:41.436Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Adsorption of hydrogen atoms on a single graphite sheet (graphene) has been investigated by first-principles electronic structure means, employing plane-wave based periodic density functional theory. A 5×5 surface unit cell has been adopted to study single and multiple adsorptions of H atoms. Binding and barrier energies for sequential sticking have been computed for a number of configurations involving adsorption on top of carbon atoms. We find that binding energies per atom range from ∼0.8 to ∼1.9 eV, with barriers to sticking in the range 0.0-0.15 eV. In addition, depending on the number and location of adsorbed hydrogen atoms, we find that magnetic structures may form in which spin density localizes on a 3×3R30° sublattice and that binding (barrier) energies for sequential adsorption increase (decrease) linearly with the site-integrated magnetization. These results can be rationalized with the help of the valence-bond resonance theory of planar π conjugated systems and suggest that preferential sticking due to barrierless adsorption is limited to formation of hydrogen pairs. © 2009 American Institute of Physics.},
 bibtype = {article},
 author = {Casolo, S. and Løvvik, O.M. and Martinazzo, R. and Tantardini, G.F.},
 doi = {10.1063/1.3072333},
 journal = {Journal of Chemical Physics},
 number = {5}
}

Adsorption of hydrogen atoms on a single graphite sheet (graphene) has been investigated by first-principles electronic structure means, employing plane-wave based periodic density functional theory. A 5×5 surface unit cell has been adopted to study single and multiple adsorptions of H atoms. Binding and barrier energies for sequential sticking have been computed for a number of configurations involving adsorption on top of carbon atoms. We find that binding energies per atom range from ∼0.8 to ∼1.9 eV, with barriers to sticking in the range 0.0-0.15 eV. In addition, depending on the number and location of adsorbed hydrogen atoms, we find that magnetic structures may form in which spin density localizes on a 3×3R30° sublattice and that binding (barrier) energies for sequential adsorption increase (decrease) linearly with the site-integrated magnetization. These results can be rationalized with the help of the valence-bond resonance theory of planar π conjugated systems and suggest that preferential sticking due to barrierless adsorption is limited to formation of hydrogen pairs. © 2009 American Institute of Physics.

@article{
 title = {Quantum dynamics of the Eley-Rideal hydrogen formation reaction on graphite at typical interstellar cloud conditions},
 type = {article},
 year = {2009},
 volume = {113},
 id = {693d6c60-06d8-3f7d-be61-4e5552c00313},
 created = {2018-01-15T12:23:04.915Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:42.280Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Eley - Rideal formation of hydrogen molecules on graphite, as well as competing collision induced processes, are investigated quantum dynamically at typical interstellar cloud conditions, focusing in particular on gasphase temperatures below 100 K, where much of the chemistry of the so-called diffuse clouds takes place on the surface of bare carbonaceous dust grains. Collisions of gas-phase hydrogen atoms with both chemisorbed and physisorbed species are considered using available potential energy surfaces (Sha et al., J. Chem. Phys.2002 116, 7158), and state-to-state, energy-resolved cross sections are computed for a number of initial vibrational states of the hydrogen atoms bound to the surface. Results show that (i) product molecules are internally hot in both cases, with vibrational distributions sharply peaked around few (one or two) vibrational levels, and (ii) cross sections for chemisorbed species are 2-3 × smaller than those for physisorbed ones. In particular, we find that H  2  formation cross sections out of chemically bound species decrease steadily when the temperature drops below ∼1000 K, and this is likely due to a quantum reflection phenomenon. This suggests that such Eley-Rideal reaction is all but efficient in the relevant gas-phase temperature range, even when gas-phase H atoms happen to chemisorb barrierless to the surface as observed, e.g., for forming so-called para dimers. Comparison with results from classical trajectory calculations highlights the need of a quantum description of the dynamics in the astrophysically relevant energy range, whereas preliminary results of an extensive first-principles investigation of the reaction energetics reveal the importance of the adopted substrate model. © 2009 American Chemical Society.},
 bibtype = {article},
 author = {Casolo, S. and Martinazzo, R. and Bonfanti, M. and Tantardini, G.F.},
 doi = {10.1021/jp9040265},
 journal = {Journal of Physical Chemistry A},
 number = {52}
}

Eley - Rideal formation of hydrogen molecules on graphite, as well as competing collision induced processes, are investigated quantum dynamically at typical interstellar cloud conditions, focusing in particular on gasphase temperatures below 100 K, where much of the chemistry of the so-called diffuse clouds takes place on the surface of bare carbonaceous dust grains. Collisions of gas-phase hydrogen atoms with both chemisorbed and physisorbed species are considered using available potential energy surfaces (Sha et al., J. Chem. Phys.2002 116, 7158), and state-to-state, energy-resolved cross sections are computed for a number of initial vibrational states of the hydrogen atoms bound to the surface. Results show that (i) product molecules are internally hot in both cases, with vibrational distributions sharply peaked around few (one or two) vibrational levels, and (ii) cross sections for chemisorbed species are 2-3 × smaller than those for physisorbed ones. In particular, we find that H 2 formation cross sections out of chemically bound species decrease steadily when the temperature drops below ∼1000 K, and this is likely due to a quantum reflection phenomenon. This suggests that such Eley-Rideal reaction is all but efficient in the relevant gas-phase temperature range, even when gas-phase H atoms happen to chemisorb barrierless to the surface as observed, e.g., for forming so-called para dimers. Comparison with results from classical trajectory calculations highlights the need of a quantum description of the dynamics in the astrophysically relevant energy range, whereas preliminary results of an extensive first-principles investigation of the reaction energetics reveal the importance of the adopted substrate model. © 2009 American Chemical Society.

@article{
 title = {Symmetry-induced gap opening in graphene superlattices},
 type = {article},
 year = {2009},
 pages = {245420},
 volume = {81},
 websites = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.81.245420,https://link.aps.org/doi/10.1103/PhysRevB.81.245420,http://arxiv.org/abs/0910.2407,http://dx.doi.org/10.1103/PhysRevB.81.245420},
 month = {10},
 publisher = {American Physical Society},
 day = {13},
 id = {73a388a3-7678-3c89-bf32-349a50c10f82},
 created = {2022-06-16T08:00:39.822Z},
 accessed = {2022-06-16},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2024-10-17T22:49:18.200Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {We study nxn honeycomb superlattices of defects in graphene. The considered defects are missing p_z orbitals and can be realized by either introducing C atom vacancies or chemically binding simple atomic species at the given sites. Using symmetry arguments we show how it is possible to open a gap when n=3m+1,3m+2 (m integer), and estimate its value to have an approximate square-root dependence on the defect concentration x=1/n^2. Tight-binding calculations confirm these findings and show that the induced-gaps can be quite large, e.g. ~100 meV for x~10^-3. Gradient-corrected density functional theory calculations on a number of superlattices made by H atoms adsorbed on graphene are in good agreement with tight-binding results, thereby suggesting that the proposed structures may be used in practice to open a gap in graphene.},
 bibtype = {article},
 author = {Martinazzo, Rocco and Casolo, Simone and Tantardini, Gian Franco},
 doi = {10.1103/PhysRevB.81.245420},
 journal = {Physical Review B},
 number = {24}
}

We study nxn honeycomb superlattices of defects in graphene. The considered defects are missing p_z orbitals and can be realized by either introducing C atom vacancies or chemically binding simple atomic species at the given sites. Using symmetry arguments we show how it is possible to open a gap when n=3m+1,3m+2 (m integer), and estimate its value to have an approximate square-root dependence on the defect concentration x=1/n^2. Tight-binding calculations confirm these findings and show that the induced-gaps can be quite large, e.g. ~100 meV for x~10^-3. Gradient-corrected density functional theory calculations on a number of superlattices made by H atoms adsorbed on graphene are in good agreement with tight-binding results, thereby suggesting that the proposed structures may be used in practice to open a gap in graphene.

@article{
 title = {Quasi-classical trajectory study of the adiabatic reactions occurring on the two lowest-lying electronic states of the LiH<inf>2</inf><sup>+</sup>system},
 type = {article},
 year = {2008},
 volume = {10},
 id = {6afdaf0d-8f4a-32e0-b286-8d9be40a40fd},
 created = {2018-01-15T12:23:06.405Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:43.046Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Quasi-classical trajectory calculations have been performed on the adiabatically allowed reactions taking place on the two lowest-lying electronic states of the LiH 2 + system, using the ab initio potential energy surfaces of Martinazzo et al. (J. Chem. Phys., 2003, 119, 11 241). These reactions comprise: (i) the exoergic H 2 and H 2 + formation occurring through LiH + + H and LiH + H + collisions in the ground and in the first electronically excited state, respectively; (ii) the endoergic (ground state) LiH + dissociation induced by collisions with H atoms; and (iii) the endoergic (excited state) Li + H 2 + → LiH + H + reaction. The topic is of relevance for a better understanding of the lithium chemistry in the early universe. Thermal rate constants for the above reactions have been computed in the temperature range 10-5000 K and found in reasonably good agreement with estimates based on the capture model. © the Owner Societies.},
 bibtype = {article},
 author = {Pino, I. and Martinazzo, R. and Tantardini, G.F.},
 doi = {10.1039/b805750h},
 journal = {Physical Chemistry Chemical Physics},
 number = {36}
}

Quasi-classical trajectory calculations have been performed on the adiabatically allowed reactions taking place on the two lowest-lying electronic states of the LiH 2 + system, using the ab initio potential energy surfaces of Martinazzo et al. (J. Chem. Phys., 2003, 119, 11 241). These reactions comprise: (i) the exoergic H 2 and H 2 + formation occurring through LiH + + H and LiH + H + collisions in the ground and in the first electronically excited state, respectively; (ii) the endoergic (ground state) LiH + dissociation induced by collisions with H atoms; and (iii) the endoergic (excited state) Li + H 2 + → LiH + H + reaction. The topic is of relevance for a better understanding of the lithium chemistry in the early universe. Thermal rate constants for the above reactions have been computed in the temperature range 10-5000 K and found in reasonably good agreement with estimates based on the capture model. © the Owner Societies.

@article{
 title = {Physisorption and diffusion of hydrogen atoms on graphite from correlated calculations on the H-coronene model system},
 type = {article},
 year = {2007},
 volume = {111},
 id = {8fe8a7e7-819f-3469-9c4c-24e2b5f98406},
 created = {2018-01-15T12:23:07.305Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:41.828Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Correlated, counterpoise corrected wave function calculations on the hydrogen-coronene system are used to investigate the energy landscape and the dynamic behavior of hydrogen atoms physisorbed on graphite. The adopted MP2 correlation level, employing the aug-cc-pVDZ basis set augmented with bond functions, has been selected after extensive investigation on the smaller hydrogen-benzene system. The computed physisorption energy (39.7 meV) is in excellent agreement with the existing experimental value of (39.2 ± 0.5) meV for a graphite single layer (Ghio, E.; Mattera, L.; Salvo, C.; Tommasini, F.; Valbusa, U. J. Chem. Phys. 1980, 73, 557) and makes one confident of the computed barriers to diffusion. A simple, analytical expression of the corrugated potential energy surface fitted to the calculated energy values is then used in 3D quantum dynamical calculations of the tunneling contribution to the diffusion coefficient. Results show that hydrogen atoms physisorbed on graphite are highly mobile on the surface even at T = 0 K. This suggests that hydrogen formation in cold, interstellar clouds can indeed occur down to very low temperatures through recombination of hydrogen atoms previously physisorbed on the surface of dust grains. © 2007 American Chemical Society.},
 bibtype = {article},
 author = {Bonfanti, M. and Martinazzo, R. and Tantardini, G.F. and Ponti, A.},
 doi = {10.1021/jp070616b},
 journal = {Journal of Physical Chemistry C},
 number = {16}
}

Correlated, counterpoise corrected wave function calculations on the hydrogen-coronene system are used to investigate the energy landscape and the dynamic behavior of hydrogen atoms physisorbed on graphite. The adopted MP2 correlation level, employing the aug-cc-pVDZ basis set augmented with bond functions, has been selected after extensive investigation on the smaller hydrogen-benzene system. The computed physisorption energy (39.7 meV) is in excellent agreement with the existing experimental value of (39.2 ± 0.5) meV for a graphite single layer (Ghio, E.; Mattera, L.; Salvo, C.; Tommasini, F.; Valbusa, U. J. Chem. Phys. 1980, 73, 557) and makes one confident of the computed barriers to diffusion. A simple, analytical expression of the corrugated potential energy surface fitted to the calculated energy values is then used in 3D quantum dynamical calculations of the tunneling contribution to the diffusion coefficient. Results show that hydrogen atoms physisorbed on graphite are highly mobile on the surface even at T = 0 K. This suggests that hydrogen formation in cold, interstellar clouds can indeed occur down to very low temperatures through recombination of hydrogen atoms previously physisorbed on the surface of dust grains. © 2007 American Chemical Society.

@article{
 title = {Chemistry at surfaces: From ab initio structures to quantum dynamics},
 type = {article},
 year = {2007},
 keywords = {Adsorption and reaction at surfaces,Dynamical simulations,Dynamics at surfaces,Molecule surface interactions,Supercell DFT calculations},
 volume = {117},
 id = {d2435e81-02bb-35ff-954e-6bd752a63e3d},
 created = {2018-01-15T12:23:09.542Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:43.048Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Recent years have witnessed an ever growing interest in theoretically studying chemical processes at surfaces. Apart from the interest in catalysis, electrochemistry, hydrogen economy, green chemistry, atmospheric and interstellar chemistry, theoretical understanding of the molecule-surface chemical bonding and of the microscopic dynamics of adsorption and reaction of adsorbates are of fundamental importance for modeling known processes, understanding new experimental data, predicting new phenomena, controlling reaction pathways. In this work, we review the efforts we have made in the last few years in this exciting field. We first consider the energetics and the structural properties of some adsorbates on metal surfaces, as deduced by converged, first-principles, plane-wave calculations within the slab-supercell approach. These studies comprise water adsorption on Ru(0001), a subject of very intense debate in the past few years, and oxygen adsorption on aluminum, the prototypical example of metal passivation. Next, we address dynamical processes at surfaces with classical and quantum methods. Here the main interest is in hydrogen dynamics on metallic and semi-metallic surfaces, because of its importance for hydrogen storage and interstellar chemistry. Hydrogen sticking is studied with classical and quasi-classical means, with particular emphasis on the relaxation of hot-atoms following dissociative chemisorption. Hot atoms dynamics on metal surfaces is investigated in the reverse, hydrogen recombination process and compared to Eley-Rideal dynamics. Finally, Eley-Rideal, collision-induced desorption, and adsorbate-induced trapping are studied quantum mechanically on a graphite surface, and unexpected quantum effects are observed. © Springer-Verlag 2007.},
 bibtype = {article},
 author = {Lanzani, G. and Martinazzo, R. and Materzanini, G. and Pino, I. and Tantardini, G.F.},
 doi = {10.1007/s00214-006-0201-6},
 journal = {Theoretical Chemistry Accounts},
 number = {5-6}
}

Recent years have witnessed an ever growing interest in theoretically studying chemical processes at surfaces. Apart from the interest in catalysis, electrochemistry, hydrogen economy, green chemistry, atmospheric and interstellar chemistry, theoretical understanding of the molecule-surface chemical bonding and of the microscopic dynamics of adsorption and reaction of adsorbates are of fundamental importance for modeling known processes, understanding new experimental data, predicting new phenomena, controlling reaction pathways. In this work, we review the efforts we have made in the last few years in this exciting field. We first consider the energetics and the structural properties of some adsorbates on metal surfaces, as deduced by converged, first-principles, plane-wave calculations within the slab-supercell approach. These studies comprise water adsorption on Ru(0001), a subject of very intense debate in the past few years, and oxygen adsorption on aluminum, the prototypical example of metal passivation. Next, we address dynamical processes at surfaces with classical and quantum methods. Here the main interest is in hydrogen dynamics on metallic and semi-metallic surfaces, because of its importance for hydrogen storage and interstellar chemistry. Hydrogen sticking is studied with classical and quasi-classical means, with particular emphasis on the relaxation of hot-atoms following dissociative chemisorption. Hot atoms dynamics on metal surfaces is investigated in the reverse, hydrogen recombination process and compared to Eley-Rideal dynamics. Finally, Eley-Rideal, collision-induced desorption, and adsorbate-induced trapping are studied quantum mechanically on a graphite surface, and unexpected quantum effects are observed. © Springer-Verlag 2007.

@article{
 title = {Quantum study of Eley-Rideal reaction and collision induced desorption of hydrogen atoms on a graphite surface. I. H-chemisorbed case},
 type = {article},
 year = {2006},
 volume = {124},
 id = {d708c9af-2ee0-3557-98f9-b1715a176e1c},
 created = {2018-01-15T12:23:02.576Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:42.426Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Collision induced (CI) processes involving hydrogen atoms on a graphite surface are studied quantum mechanically within the rigid, flat surface approximation, using a time-dependent wave packet method. The Eley-Rideal (ER) reaction and collision induced desorption (CID) cross sections are obtained with the help of two propagations which use different sets of coordinates, a "product" and a "reagent" set. Several adsorbate-substrate initial states of the target H atom in the chemisorption well are considered, and CI processes are studied over a wide range of projectile energy. Results show that (i) the Eley-Rideal reaction is the major reactive outcome and (ii) CID cross sections do not exceed 4 Å2 and present dynamic thresholds for low values of the target vibrational quantum number. ER cross sections show oscillations at high energies which cannot be reproduced by classical and quasiclassical trajectory calculations. They are related to the vibrational excitation of the reaction products, which is a rather steep decreasing function of the collision energy. This behavior causes a selective population of the low-lying vibrational states and allows the quantization of the product molecular states to manifest itself in a collisional observable. A peak structure in the CID cross section is also observed and is assigned to the selective population of metastable states of the transient molecular hydrogen. © 2006 American Institute of Physics.},
 bibtype = {article},
 author = {Martinazzo, R. and Tantardini, G.F.},
 doi = {10.1063/1.2177654},
 journal = {Journal of Chemical Physics},
 number = {12}
}

Collision induced (CI) processes involving hydrogen atoms on a graphite surface are studied quantum mechanically within the rigid, flat surface approximation, using a time-dependent wave packet method. The Eley-Rideal (ER) reaction and collision induced desorption (CID) cross sections are obtained with the help of two propagations which use different sets of coordinates, a "product" and a "reagent" set. Several adsorbate-substrate initial states of the target H atom in the chemisorption well are considered, and CI processes are studied over a wide range of projectile energy. Results show that (i) the Eley-Rideal reaction is the major reactive outcome and (ii) CID cross sections do not exceed 4 Å2 and present dynamic thresholds for low values of the target vibrational quantum number. ER cross sections show oscillations at high energies which cannot be reproduced by classical and quasiclassical trajectory calculations. They are related to the vibrational excitation of the reaction products, which is a rather steep decreasing function of the collision energy. This behavior causes a selective population of the low-lying vibrational states and allows the quantization of the product molecular states to manifest itself in a collisional observable. A peak structure in the CID cross section is also observed and is assigned to the selective population of metastable states of the transient molecular hydrogen. © 2006 American Institute of Physics.

@article{
 title = {Quantum study of Eley-Rideal reaction and collision induced desorption of hydrogen atoms on a graphite surface. II. H-physisorbed case},
 type = {article},
 year = {2006},
 volume = {124},
 id = {113e4823-650b-3f85-8387-5144c8aac216},
 created = {2018-01-15T12:23:02.708Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:41.849Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Following previous investigation of collision induced (CI) processes involving hydrogen atoms chemisorbed on graphite [R. Martinazzo and G. F. Tantardini, J. Chem. Phys. 124, 124702 (2006)], the case in which the target hydrogen atom is initially physisorbed on the surface is considered here. Several adsorbate-substrate initial states of the target H atom in the physisorption well are considered, and CI processes are studied for projectile energies up to 1 eV. Results show that (i) Eley-Rideal cross sections at low collision energies may be larger than those found in the H-chemisorbed case but they rapidly decrease as the collision energy increases; (ii) product hydrogen molecules are vibrationally very excited; (iii) collision induced desorption cross sections rapidly increase, reaching saturation values greater than 10 Å2; (iv) trapping of the incident atoms is found to be as efficient as the Eley-Rideal reaction at low energies and remains sizable (3-4 Å2) at high energies. The latter adsorbate-induced trapping results mainly in formation of metastable hot hydrogen atoms, i.e., atoms with an excess energy channeled in the motion parallel to the surface. These atoms might contribute in explaining hydrogen formation on graphite. © 2006 American Institute of Physics.},
 bibtype = {article},
 author = {Martinazzo, R. and Tantardini, G.F.},
 doi = {10.1063/1.2177655},
 journal = {Journal of Chemical Physics},
 number = {12}
}

Following previous investigation of collision induced (CI) processes involving hydrogen atoms chemisorbed on graphite [R. Martinazzo and G. F. Tantardini, J. Chem. Phys. 124, 124702 (2006)], the case in which the target hydrogen atom is initially physisorbed on the surface is considered here. Several adsorbate-substrate initial states of the target H atom in the physisorption well are considered, and CI processes are studied for projectile energies up to 1 eV. Results show that (i) Eley-Rideal cross sections at low collision energies may be larger than those found in the H-chemisorbed case but they rapidly decrease as the collision energy increases; (ii) product hydrogen molecules are vibrationally very excited; (iii) collision induced desorption cross sections rapidly increase, reaching saturation values greater than 10 Å2; (iv) trapping of the incident atoms is found to be as efficient as the Eley-Rideal reaction at low energies and remains sizable (3-4 Å2) at high energies. The latter adsorbate-induced trapping results mainly in formation of metastable hot hydrogen atoms, i.e., atoms with an excess energy channeled in the motion parallel to the surface. These atoms might contribute in explaining hydrogen formation on graphite. © 2006 American Institute of Physics.

@article{
 title = {A local coherent-state approximation to system-bath quantum dynamics},
 type = {article},
 year = {2006},
 volume = {125},
 id = {bf04394e-d4f4-331e-b3ea-1a8bbe934ed4},
 created = {2018-01-15T12:23:03.910Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:40.985Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {A novel quantum method to deal with typical system-bath dynamical problems is introduced. Subsystem discrete variable representation and bath coherent-state sets are used to write down a multiconfigurational expansion of the wave function of the whole system. With the help of the Dirac-Frenkel variational principle, simple equations of motion-a kind of Schrödinger- Langevin equation for the subsystem coupled to (pseudo) classical equations for the bath-are derived. True dissipative dynamics at all times is obtained by coupling the bath to a secondary, classical Ohmic bath, which is modeled by adding a friction coefficient in the derived pseudoclassical bath equations. The resulting equations are then solved for a number of model problems, ranging from tunneling to vibrational relaxation dynamics. Comparison of the results with those of exact, multiconfiguration time-dependent Hartree calculations in systems with up to 80 bath oscillators shows that the proposed method can be very accurate and might be of help in studying realistic problems with very large baths. To this end, its linear scaling behavior with respect to the number of bath degrees of freedom is shown in practice with model calculations using tens of thousands of bath oscillators. © 2006 American Institute of Physics.},
 bibtype = {article},
 author = {Martinazzo, R. and Nest, M. and Saalfrank, P. and Tantardini, G.F.},
 doi = {10.1063/1.2362821},
 journal = {Journal of Chemical Physics},
 number = {19}
}

A novel quantum method to deal with typical system-bath dynamical problems is introduced. Subsystem discrete variable representation and bath coherent-state sets are used to write down a multiconfigurational expansion of the wave function of the whole system. With the help of the Dirac-Frenkel variational principle, simple equations of motion-a kind of Schrödinger- Langevin equation for the subsystem coupled to (pseudo) classical equations for the bath-are derived. True dissipative dynamics at all times is obtained by coupling the bath to a secondary, classical Ohmic bath, which is modeled by adding a friction coefficient in the derived pseudoclassical bath equations. The resulting equations are then solved for a number of model problems, ranging from tunneling to vibrational relaxation dynamics. Comparison of the results with those of exact, multiconfiguration time-dependent Hartree calculations in systems with up to 80 bath oscillators shows that the proposed method can be very accurate and might be of help in studying realistic problems with very large baths. To this end, its linear scaling behavior with respect to the number of bath degrees of freedom is shown in practice with model calculations using tens of thousands of bath oscillators. © 2006 American Institute of Physics.

@article{
 title = {Testing wave packet dynamics in computing radiative association cross sections},
 type = {article},
 year = {2005},
 volume = {122},
 id = {f10eb4be-bbf6-3647-b77b-48931188b0ad},
 created = {2018-01-15T12:23:02.786Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:42.354Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {A time-dependent wave packet method is used to compute cross sections for radiative recombination reactions using the Li( 2 S)+H + →LiH + (X 2 Σ + )+γ as a test case. Cross sections are calculated through standard time-to-energy mapping of the time-dependent transition moment and a useful method is introduced to deal with the low collision energy regime. Results are in quantitative agreement over the whole energy range 10 -4 -5 eV with previous time-independent results for the same system [I. Baccarelli, L. Andric, T. Grozdanov, and R. McCarroll, J. Chem. Phys. 117, 3013 (2002)], thereby suggesting that the method can be of help in computing radiative association cross sections for more complicated systems.},
 bibtype = {article},
 author = {Martinazzo, R. and Tantardini, G.F.},
 doi = {10.1063/1.1857476},
 journal = {Journal of Chemical Physics},
 number = {9}
}

A time-dependent wave packet method is used to compute cross sections for radiative recombination reactions using the Li( 2 S)+H + →LiH + (X 2 Σ + )+γ as a test case. Cross sections are calculated through standard time-to-energy mapping of the time-dependent transition moment and a useful method is introduced to deal with the low collision energy regime. Results are in quantitative agreement over the whole energy range 10 -4 -5 eV with previous time-independent results for the same system [I. Baccarelli, L. Andric, T. Grozdanov, and R. McCarroll, J. Chem. Phys. 117, 3013 (2002)], thereby suggesting that the method can be of help in computing radiative association cross sections for more complicated systems.

@article{
 title = {Quantum effects in an exoergic, barrierless reaction at high collision energies},
 type = {article},
 year = {2005},
 volume = {109},
 id = {d9bb5ed1-89e3-3989-9734-d9615dd41a16},
 created = {2018-01-15T12:23:02.868Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:41.766Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The exoergic Eley-Rideal hydrogen recombination on graphite surfaces is known to produce vibrationally hot product molecules. Realistic quantum scattering calculations at normal incidence over a wide range of collision energies show that the degree of vibrational excitation of the reaction product is a steep decreasing function of the collision energy. This results in selective population of the lower-lying vibrational levels and gives rise to an oscillating structure in the total reaction cross-sections at high energies, which cannot be reproduced by classical and quasi-classical trajectory calculations. An analogous quantum structure appears in the total collision-induced desorption cross-sections and is assigned to selective population of the metastable states of the transient molecular hydrogen. © 2005 American Chemical Society.},
 bibtype = {article},
 author = {Martinazzo, R. and Tantardini, G.F.},
 doi = {10.1021/jp053820c},
 journal = {Journal of Physical Chemistry A},
 number = {42}
}

The exoergic Eley-Rideal hydrogen recombination on graphite surfaces is known to produce vibrationally hot product molecules. Realistic quantum scattering calculations at normal incidence over a wide range of collision energies show that the degree of vibrational excitation of the reaction product is a steep decreasing function of the collision energy. This results in selective population of the lower-lying vibrational levels and gives rise to an oscillating structure in the total reaction cross-sections at high energies, which cannot be reproduced by classical and quasi-classical trajectory calculations. An analogous quantum structure appears in the total collision-induced desorption cross-sections and is assigned to selective population of the metastable states of the transient molecular hydrogen. © 2005 American Chemical Society.

@article{
 title = {Hot-atom versus Eley-Rideal dynamics in hydrogen recombination on Ni(100). I. The single-adsorbate case},
 type = {article},
 year = {2004},
 volume = {120},
 id = {9f95c7c5-3ec3-3736-8e64-66aef7b88926},
 created = {2018-01-15T12:23:03.681Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:42.786Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The scattering of a projectile hydrogen atom off a target hydrogen atom adsorbed on the Ni(100) surface was studied. Both the rigid and the moving surface cases were considered and the results were compared over a wide range of collision energies and for different aiming cells. Particular attention was paid to the process of energy transfer while studying the collision system in the presence of an explicit thermal bath. The problems associated with the use of PBCs were approximately solved by breaking the dynamics into two steps.},
 bibtype = {article},
 author = {Martinazzo, R. and Assoni, S. and Marinoni, G. and Tantardini, G.F.},
 doi = {10.1063/1.1695316},
 journal = {Journal of Chemical Physics},
 number = {18}
}

The scattering of a projectile hydrogen atom off a target hydrogen atom adsorbed on the Ni(100) surface was studied. Both the rigid and the moving surface cases were considered and the results were compared over a wide range of collision energies and for different aiming cells. Particular attention was paid to the process of energy transfer while studying the collision system in the presence of an explicit thermal bath. The problems associated with the use of PBCs were approximately solved by breaking the dynamics into two steps.

@article{
 title = {Potential energy surface, bound states, and rotational inelastic cross sections of the He-CH<inf>4</inf>system: A theoretical Investigation},
 type = {article},
 year = {2004},
 volume = {121},
 id = {97c404a0-c43f-368d-bbfd-a88515eb7de4},
 created = {2018-01-15T12:23:05.260Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:41.843Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {We determined two potential energy surfaces (PES) for the He-CH 4 system by means of MP4 and Valence Bond (VB) calculations. The MP4 potential is similar to the one commonly adopted for this system [U. Buck, K. H. Kohl, A. Kolhase, M. Faubel, and U. Staemmler, Mol. Phys. 55, 1255 (1985)], while the VB PES is slightly more attractive. To evaluate the reliability of these potentials, we investigated the scattering properties by performing close coupling calculations, and concluded that: (i) the available experimental data do not permit the ranking among the PES considered; (ii) some theoretical predictions differ considerably from the experimental data, and these discrepancies cannot entirely be ascribed to the inaccuracy of the ab initio calculations; (iii) the scattering properties at low energy might discriminate between the MP4 and VB potentials. © 2004 American Institute of Physics.},
 bibtype = {article},
 author = {Calderoni, G. and Cargnoni, F. and Martinazzo, R. and Raimondi, M.},
 doi = {10.1063/1.1791111},
 journal = {Journal of Chemical Physics},
 number = {17}
}

We determined two potential energy surfaces (PES) for the He-CH 4 system by means of MP4 and Valence Bond (VB) calculations. The MP4 potential is similar to the one commonly adopted for this system [U. Buck, K. H. Kohl, A. Kolhase, M. Faubel, and U. Staemmler, Mol. Phys. 55, 1255 (1985)], while the VB PES is slightly more attractive. To evaluate the reliability of these potentials, we investigated the scattering properties by performing close coupling calculations, and concluded that: (i) the available experimental data do not permit the ranking among the PES considered; (ii) some theoretical predictions differ considerably from the experimental data, and these discrepancies cannot entirely be ascribed to the inaccuracy of the ab initio calculations; (iii) the scattering properties at low energy might discriminate between the MP4 and VB potentials. © 2004 American Institute of Physics.

@article{
 title = {The gas-phase lithium chemistry in the early universe: Elementary processes, interaction forces and quantum dynamics},
 type = {article},
 year = {2003},
 keywords = {Molecular chemistry,Quantum chemistry},
 volume = {384},
 id = {4ed848c3-8af1-33d6-badf-c120ba29184c},
 created = {2018-01-15T12:23:03.362Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:42.543Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {In this work we review the efforts made in the last 10 years to understand the neutral and ionic chemistry of LiH. The relevance of most of the studies on this subject is due to the possible importance of the LiH molecules and relative ions in the primordial universe chemistry. Although it is still not clear what could be the role of LiH in the early universe chemistry, since experimentally important data are indeed still missing and its relevance may be limited by the small abundance of Li molecular species that is thought to exist at the recombination era, it is already important from a fundamental point of view to gather the various results obtained up to now since, in our opinion, they are already able to shed light on a large portion of the gas-phase chemistry of LiH and of its positive ion. Most of the results that will be summarized here are theoretical and computational, intending to provide the present state of our knowledge on the relevant potential energy surfaces and dynamical processes which ensue from their features. © 2003 Elsevier B.V. All rights reserved.},
 bibtype = {article},
 author = {Bodo, E. and Gianturco, F.A. and Martinazzo, R.},
 doi = {10.1016/S0370-1573(03)00243-6},
 journal = {Physics Reports},
 number = {3}
}

In this work we review the efforts made in the last 10 years to understand the neutral and ionic chemistry of LiH. The relevance of most of the studies on this subject is due to the possible importance of the LiH molecules and relative ions in the primordial universe chemistry. Although it is still not clear what could be the role of LiH in the early universe chemistry, since experimentally important data are indeed still missing and its relevance may be limited by the small abundance of Li molecular species that is thought to exist at the recombination era, it is already important from a fundamental point of view to gather the various results obtained up to now since, in our opinion, they are already able to shed light on a large portion of the gas-phase chemistry of LiH and of its positive ion. Most of the results that will be summarized here are theoretical and computational, intending to provide the present state of our knowledge on the relevant potential energy surfaces and dynamical processes which ensue from their features. © 2003 Elsevier B.V. All rights reserved.

@article{
 title = {A modified variable-phase algorithm for multichannel scattering with long-range potentials},
 type = {article},
 year = {2003},
 volume = {151},
 id = {86da04e0-aea1-3eed-b46e-2309b091f548},
 created = {2018-01-15T12:23:04.103Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:41.668Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {A new Variable-Phase (VP) algorithm for solving the close coupled equations of inelastic scattering in atom-molecule collisions driven by a strong long range potential is presented. The proposed method allows for a rigorous, gradual reduction of the number of closed channels during the outward propagation of the solution of the VP equations. In this way it allows a considerable saving of CPU time when dealing with strong, long-range potentials. A further saving of computational time is achieved by the use of a zero order effective potential in the reference problem which avoids the calculation of the computationally expensive Bessel functions. The K matrix version of the VP equations are solved with a standard Runge-Kutta integrator with adaptive step size. The low-energy, rotational excitation process in the LiH-H + system is used to test the resulting algorithm and we show that the present method once applied to long-range interactions, can be orders of magnitude faster than the widely used, adaptive-step size LogDerivative/Airy propagator while keeping the same level of accuracy. © 2002 Elsevier Science B.V. All rights reserved.},
 bibtype = {article},
 author = {Martinazzo, R. and Bodo, E. and Gianturco, F.A.},
 doi = {10.1016/S0010-4655(02)00737-3},
 journal = {Computer Physics Communications},
 number = {2}
}

A new Variable-Phase (VP) algorithm for solving the close coupled equations of inelastic scattering in atom-molecule collisions driven by a strong long range potential is presented. The proposed method allows for a rigorous, gradual reduction of the number of closed channels during the outward propagation of the solution of the VP equations. In this way it allows a considerable saving of CPU time when dealing with strong, long-range potentials. A further saving of computational time is achieved by the use of a zero order effective potential in the reference problem which avoids the calculation of the computationally expensive Bessel functions. The K matrix version of the VP equations are solved with a standard Runge-Kutta integrator with adaptive step size. The low-energy, rotational excitation process in the LiH-H + system is used to test the resulting algorithm and we show that the present method once applied to long-range interactions, can be orders of magnitude faster than the widely used, adaptive-step size LogDerivative/Airy propagator while keeping the same level of accuracy. © 2002 Elsevier Science B.V. All rights reserved.

@article{
 title = {Accurate potential energy surfaces for the study of lithium-hydrogen ionic reactions},
 type = {article},
 year = {2003},
 volume = {119},
 id = {026629f9-35be-3aaf-9ca6-c588c5147867},
 created = {2018-01-15T12:23:04.395Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:41.360Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Accurate ab initio energy values for the LiH 2 + system was computed and fitted. Focus was on the two lowest lying electronic states which are found well separated in energy and therefore can be reated rather realistically as being adiabatical. As a result, the LiH/LiH + exoergic, depletion reactions were characterized in detail.},
 bibtype = {article},
 author = {Martinazzo, R. and Tantardini, G.F. and Bodo, E. and Gianturco, F.A.},
 doi = {10.1063/1.1621852},
 journal = {Journal of Chemical Physics},
 number = {21}
}

Accurate ab initio energy values for the LiH 2 + system was computed and fitted. Focus was on the two lowest lying electronic states which are found well separated in energy and therefore can be reated rather realistically as being adiabatical. As a result, the LiH/LiH + exoergic, depletion reactions were characterized in detail.

@article{
 title = {Three-dimensional reactive surfaces for the LiH<inf>2</inf><sup>+</sup>system: An analysis of accurate ab initio results},
 type = {article},
 year = {2003},
 volume = {287},
 id = {68120832-2c30-3e85-beaa-107b8daefc60},
 created = {2018-01-15T12:23:08.318Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:41.595Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Calculations for the reactive potential energy surfaces, which are relevant for examining the low-energy channels connected with the LiH 2 + three atom ionic system, are carried out using a multireference valence bond (MRVB) approach. More than 11000 points have been computed over the grid of the three relevant coordinates (two bond distances and the enclosed angle) and the lowest three electronic states have been followed over the spatial configuration of the above coordinates. Several aspects of the reactive behavior could be gleaned from an analysis of the computed surfaces and various features of the reactive outcomes are extracted from that analysis. © 2002 Elsevier Science B.V. All rights reserved.},
 bibtype = {article},
 author = {Martinazzo, R. and Bodo, E. and Gianturco, F.A. and Raimondi, M.},
 doi = {10.1016/S0301-0104(02)01021-2},
 journal = {Chemical Physics},
 number = {3}
}

Calculations for the reactive potential energy surfaces, which are relevant for examining the low-energy channels connected with the LiH 2 + three atom ionic system, are carried out using a multireference valence bond (MRVB) approach. More than 11000 points have been computed over the grid of the three relevant coordinates (two bond distances and the enclosed angle) and the lowest three electronic states have been followed over the spatial configuration of the above coordinates. Several aspects of the reactive behavior could be gleaned from an analysis of the computed surfaces and various features of the reactive outcomes are extracted from that analysis. © 2002 Elsevier Science B.V. All rights reserved.

@article{
 title = {Photoexcitation of LiH<inf>2</inf><sup>+</sup>from selected initial states: A time-dependent model},
 type = {article},
 year = {2002},
 volume = {117},
 id = {c66f5fe2-321a-3ff0-83a8-15d8699f564f},
 created = {2018-01-15T12:23:05.768Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:41.990Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {A quantum time-dependent treatment was employed to model the photoexcitation of LiH 2 + . The study was carried out by monitoring the fragmentation probabilities, the final vibrational distributions of the molecular fragments, and the angular evolution of the wave functions of the complex on the excited electronic surface. The comparison between different initial conditions shed light on the microscopic mechanism of the energy redistribution, with reference to the angular coordinate providing efficient energy channeling during the evolution.},
 bibtype = {article},
 author = {Satta, M. and Bodo, E. and Martinazzo, R. and Gianturco, F.A.},
 doi = {10.1063/1.1482695},
 journal = {Journal of Chemical Physics},
 number = {1}
}

A quantum time-dependent treatment was employed to model the photoexcitation of LiH 2 + . The study was carried out by monitoring the fragmentation probabilities, the final vibrational distributions of the molecular fragments, and the angular evolution of the wave functions of the complex on the excited electronic surface. The comparison between different initial conditions shed light on the microscopic mechanism of the energy redistribution, with reference to the angular coordinate providing efficient energy channeling during the evolution.

@book{
 title = {Recent developments of the SCVB method},
 type = {book},
 year = {2002},
 source = {Theoretical and Computational Chemistry},
 volume = {10},
 id = {2a8b0c5e-5065-3b44-bb72-3775d4a91035},
 created = {2018-01-15T12:23:09.778Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:40.818Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Ab initio modern valence bond theory, in its spin-coupled valence bond (SCVB) form, has proved very successful for accurate computations on ground and excited states of molecular systems. The compactness of the resulting wavefunctions allows direct and clear interpretation of correlated electronic structure. We concentrate in the present account on recent developments, typically involving the optimization of virtual orbitals via an approximate energy expression. These virtuals lead to higher accuracy for the final variational wavefunctions, but with even more compact functions. Particular attention is paid here to applications of the methodology to studies of intermolecular forces.},
 bibtype = {book},
 author = {Sironi, M. and Raimondi, M. and Martinazzo, R. and Gianturco, F.A. and Cooper, D.L.}
}

Ab initio modern valence bond theory, in its spin-coupled valence bond (SCVB) form, has proved very successful for accurate computations on ground and excited states of molecular systems. The compactness of the resulting wavefunctions allows direct and clear interpretation of correlated electronic structure. We concentrate in the present account on recent developments, typically involving the optimization of virtual orbitals via an approximate energy expression. These virtuals lead to higher accuracy for the final variational wavefunctions, but with even more compact functions. Particular attention is paid here to applications of the methodology to studies of intermolecular forces.

@article{
 title = {Reactive behavior of the [LiH<inf>2</inf>]<sup>+</sup> system II. Collision-induced dissociation and collinear reaction dynamics of LiH<sup>+</sup>+H from quantum time dependent calculations},
 type = {article},
 year = {2001},
 volume = {105},
 id = {e1d7837e-7000-34be-9835-e4b099a9ce6c},
 created = {2018-01-15T12:23:04.305Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:41.549Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The time-dependent approach to reactive scattering is applied to the study of the collinear collisions for the LiH + +H system. The reaction LiH + +H → H 2 +Li +  is adiabatically confined to the ground electronic state of the LiH 2 +  system and is highly exoergic (∼4.2 eV). However, despite the strong energetic gain, the present calculations show that the reactive component is only a negligible outcome of the encounters while the simple inelastic scattering process and the collision-induced dissociation dominate the dynamics. The binding energy of the LiH +  reagent molecule is so weak that the threshold of the triatomic dissociation channels becomes open at a collision energy of only a few tenths of an electronvolt. The total dissociation probabilities are obtained via an accurate computation of all the possible bound-to-bound transition probabilities (reactive and nonreactive) using the quantum time-dependent approach described herein.},
 bibtype = {article},
 author = {Bodo, E. and Gianturco, F.A. and Martinazzo, R.},
 doi = {10.1021/jp012344x},
 journal = {Journal of Physical Chemistry A},
 number = {49}
}

The time-dependent approach to reactive scattering is applied to the study of the collinear collisions for the LiH + +H system. The reaction LiH + +H → H 2 +Li + is adiabatically confined to the ground electronic state of the LiH 2 + system and is highly exoergic (∼4.2 eV). However, despite the strong energetic gain, the present calculations show that the reactive component is only a negligible outcome of the encounters while the simple inelastic scattering process and the collision-induced dissociation dominate the dynamics. The binding energy of the LiH + reagent molecule is so weak that the threshold of the triatomic dissociation channels becomes open at a collision energy of only a few tenths of an electronvolt. The total dissociation probabilities are obtained via an accurate computation of all the possible bound-to-bound transition probabilities (reactive and nonreactive) using the quantum time-dependent approach described herein.

@article{
 title = {Reactive behavior of the [LiH<inf>2</inf>]<sup>+</sup> system I. Evaluation of the lower-lying electronic potentials for the collinear geometries},
 type = {article},
 year = {2001},
 volume = {105},
 id = {18570e99-9426-399c-89d6-c2ccbcb82944},
 created = {2018-01-15T12:23:04.822Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:43.252Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The reactive behavior of the [LiH 2 ] +  system is investigated by computing the potential energy surfaces (PES) for the collinear geometries. The three lowest-lying PESs have been obtained using a multireference valence bond approach and subsequently have been fitted with modified Laguerre functions. The results appear to exclude any significant nonadiabatic interaction between the first two electronic states and already suggest differences in the dynamical behavior of the title system when moving on each of these potential energy surfaces. Thus, at least within a collinear approach, a direct reactive dynamics should be expected for the ground-state reaction of LiH + +H → Li + +H 2 , while the formation of a temporary complex is suggested to occur for the partners interacting via the electronically excited PES pertaining to LiH+H +  → Li+H 2 + .},
 bibtype = {article},
 author = {Bodo, E. and Gianturco, F.A. and Martinazzo, R. and Raimondi, M.},
 doi = {10.1021/jp0123435},
 journal = {Journal of Physical Chemistry A},
 number = {49}
}

The reactive behavior of the [LiH 2 ] + system is investigated by computing the potential energy surfaces (PES) for the collinear geometries. The three lowest-lying PESs have been obtained using a multireference valence bond approach and subsequently have been fitted with modified Laguerre functions. The results appear to exclude any significant nonadiabatic interaction between the first two electronic states and already suggest differences in the dynamical behavior of the title system when moving on each of these potential energy surfaces. Thus, at least within a collinear approach, a direct reactive dynamics should be expected for the ground-state reaction of LiH + +H → Li + +H 2 , while the formation of a temporary complex is suggested to occur for the partners interacting via the electronically excited PES pertaining to LiH+H + → Li+H 2 + .

@article{
 title = {Possible reaction paths in the LiH2 + chemistry: A computational analysis of the interaction forces},
 type = {article},
 year = {2001},
 volume = {271},
 id = {a6846fe4-6eb7-3e00-868f-a83d53d83fb5},
 created = {2018-01-15T12:23:06.232Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:41.639Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The present study addresses the problem of establishing from fully ab initio quantum methods some quantitative features of the chemical interactions which play an important role in the ionic lithium chemistry of astrophysical relevance. In particular, the LiH 2 + energetics is examined by looking at the various possible chemical channels producing LiH, LiH + , H 2 and H 2 + . An accurate evaluation of the relative energy landscapes as the complex breaks up into its asymptotic partners is presented for the first time. It allows us to clearly select those reactive pathways which can be excluded when setting up a kinetic modeling of the lithium chemistry network in early universe processes. © 2001 Elsevier Science B.V. All rights reserved.},
 bibtype = {article},
 author = {Bodo, E. and Gianturco, F.A. and Martinazzo, R. and Raimondi, M.},
 doi = {10.1016/S0301-0104(01)00424-4},
 journal = {Chemical Physics},
 number = {3}
}

The present study addresses the problem of establishing from fully ab initio quantum methods some quantitative features of the chemical interactions which play an important role in the ionic lithium chemistry of astrophysical relevance. In particular, the LiH 2 + energetics is examined by looking at the various possible chemical channels producing LiH, LiH + , H 2 and H 2 + . An accurate evaluation of the relative energy landscapes as the complex breaks up into its asymptotic partners is presented for the first time. It allows us to clearly select those reactive pathways which can be excluded when setting up a kinetic modeling of the lithium chemistry network in early universe processes. © 2001 Elsevier Science B.V. All rights reserved.

@article{
 title = {Computed orientational anisotropy and vibrational couplings for the LiH + H interaction potential},
 type = {article},
 year = {2001},
 volume = {15},
 id = {47be5a7a-e501-3e2a-94a5-ff405ef501e2},
 created = {2018-01-15T12:23:06.321Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:42.638Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The interaction between LiH and H has been calculated using a Coupled Cluster approach in view of examining the strength of the coupling between the impinging atom and the rovibrational LiH states in low energy collision regimes. The potential energy surface was thus obtained by considering not only the angular anisotropy but also the dependence of the interaction energy on the vibrational motion of the LiH molecule, hence producing the strength of the vibrational coupling. The main objective is that of gaining a realistic description of the interaction in the sub-reactive region. The results of our calculations show here that this interaction should be used in conjunction with that of the reactive configurational space because of the strong coupling between the non-reactive and the reactive channels in the present system makes the full reactive scattering calculations a more reliable way to obtain realistic cross-sections also for inelastic relaxation and excitation processes.},
 bibtype = {article},
 author = {Bodo, E. and Gianturco, F.A. and Martinazzo, R. and Raimondi, M.},
 doi = {10.1007/s100530170147},
 journal = {European Physical Journal D},
 number = {3}
}

The interaction between LiH and H has been calculated using a Coupled Cluster approach in view of examining the strength of the coupling between the impinging atom and the rovibrational LiH states in low energy collision regimes. The potential energy surface was thus obtained by considering not only the angular anisotropy but also the dependence of the interaction energy on the vibrational motion of the LiH molecule, hence producing the strength of the vibrational coupling. The main objective is that of gaining a realistic description of the interaction in the sub-reactive region. The results of our calculations show here that this interaction should be used in conjunction with that of the reactive configurational space because of the strong coupling between the non-reactive and the reactive channels in the present system makes the full reactive scattering calculations a more reliable way to obtain realistic cross-sections also for inelastic relaxation and excitation processes.

@article{
 title = {A multireference valence bond approach to electronic excited states},
 type = {article},
 year = {2001},
 volume = {115},
 id = {aaea929a-fe6f-3c5a-b8fe-29f187bdefc9},
 created = {2018-01-15T12:23:09.256Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:41.906Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {A multireference valence bond approach based on orthogonality conditions to ground state spin coupled (SC) orbitals was applied for the treatment of electronic excited states. Optimization of excited spin coupled wave functions was used to introduce correlation corrections in the excited state. The optimization was achieved using simple orthogonality constraints on the spin coupled orbitals.},
 bibtype = {article},
 author = {Martinazzo, R. and Famulari, A. and Raimondi, M. and Bodo, E. and Gianturco, F.A.},
 doi = {10.1063/1.1388043},
 journal = {Journal of Chemical Physics},
 number = {7}
}

A multireference valence bond approach based on orthogonality conditions to ground state spin coupled (SC) orbitals was applied for the treatment of electronic excited states. Optimization of excited spin coupled wave functions was used to introduce correlation corrections in the excited state. The optimization was achieved using simple orthogonality constraints on the spin coupled orbitals.

@article{
 title = {Applications of a variational coupled-electron pair approach to the calculation of intermolecular interaction in the framework of the VB theory: study of the van der Waals complex He-CH<inf>4</inf>},
 type = {article},
 year = {2000},
 volume = {113},
 id = {6caa8aa8-1f5e-3b10-bb2e-a43e0e0530a1},
 created = {2018-01-15T12:23:06.603Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:40.975Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The potential surfaces of the He-CH 4 complex was studied by means of a general molecular orbital-valence bond (MO-VB) ab initio approach. Correlation contributions were determined using a very compact multistructure VB wave function. Further, a scheme for the intermediation generation of two virtual orbitals was devised.},
 bibtype = {article},
 author = {Specchio, R. and Famulari, A. and Martinazzo, R. and Raimondi, M.},
 doi = {10.1063/1.1287274},
 journal = {Journal of Chemical Physics},
 number = {16}
}

The potential surfaces of the He-CH 4 complex was studied by means of a general molecular orbital-valence bond (MO-VB) ab initio approach. Correlation contributions were determined using a very compact multistructure VB wave function. Further, a scheme for the intermediation generation of two virtual orbitals was devised.

@article{
 title = {Testing van der Waals interactions with quantum dynamics: Repulsive anisotropy and well depth in the LiH+He system},
 type = {article},
 year = {2000},
 volume = {113},
 id = {0da890a7-c898-311e-81e0-44fe4c7c7ebd},
 created = {2018-01-15T12:23:08.419Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:42.102Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The rigid rotor surface for the LiH-He interaction was studied numerically. The study showed that the well depth and anisotropy of the new surface differ from the valence bond calculations. The performance of potential energy surfaces to generate quantum observables is examined. The two surfaces show small differences in their short-range repulsive anisotropy. They show larger differences in their well depths. The different behavior of their wells in supporting van der Waals bound states was examined.},
 bibtype = {article},
 author = {Bodo, E. and Gianturco, F.A. and Martinazzo, R. and Paesani, F. and Raimondi, M.},
 doi = {10.1063/1.1311801},
 journal = {Journal of Chemical Physics},
 number = {24}
}

The rigid rotor surface for the LiH-He interaction was studied numerically. The study showed that the well depth and anisotropy of the new surface differ from the valence bond calculations. The performance of potential energy surfaces to generate quantum observables is examined. The two surfaces show small differences in their short-range repulsive anisotropy. They show larger differences in their well depths. The different behavior of their wells in supporting van der Waals bound states was examined.

@article{
 title = {Spatial energetics of protonated LiH: Lower-lying potential energy surfaces from valence bond calculations},
 type = {article},
 year = {2000},
 volume = {104},
 id = {54eb0f2e-162f-3e82-90a1-2d97e097cc89},
 created = {2018-01-15T12:23:09.987Z},
 file_attached = {false},
 profile_id = {58fff4c0-32ca-3b78-a4d0-4edfe6bf3372},
 last_modified = {2022-06-07T13:55:42.178Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The detailed features of the interaction forces within the LiH 2 + triatomic system are calculated using the spin-coupled valence bond (SCVB) method in terms of the three Jacobi coordinates of the LiH(LiH + ) and H + /H fragments within a broad range of relative orientations and of internuclear distances. The specific features of the systems and of their asymptotic molecular fragments are examined with the view of estimating from them the collisional probabilities for producing rovibrationally excited partners with detectable radiative behavior. The possibility of having a charge-transfer process within the two electronic states of the LiH 2 + ion is also analyzed and discussed. The calculations suggest, albeit still qualitatively, that a direct charge-transfer reaction between LiH + H + into LiH + + H is unlikely to take place during bimolecular collisions in a low-density medium. © 2000 American Chemical Society.},
 bibtype = {article},
 author = {Bodo, E. and Gianturco, F.A. and Martinazzo, R. and Forni, A. and Famulari, A. and Raimondi, M.},
 doi = {10.1021/jp0022510},
 journal = {Journal of Physical Chemistry A},
 number = {51}
}

The detailed features of the interaction forces within the LiH 2 + triatomic system are calculated using the spin-coupled valence bond (SCVB) method in terms of the three Jacobi coordinates of the LiH(LiH + ) and H + /H fragments within a broad range of relative orientations and of internuclear distances. The specific features of the systems and of their asymptotic molecular fragments are examined with the view of estimating from them the collisional probabilities for producing rovibrationally excited partners with detectable radiative behavior. The possibility of having a charge-transfer process within the two electronic states of the LiH 2 + ion is also analyzed and discussed. The calculations suggest, albeit still qualitatively, that a direct charge-transfer reaction between LiH + H + into LiH + + H is unlikely to take place during bimolecular collisions in a low-density medium. © 2000 American Chemical Society.