Accuracy of buffered-force QM/MM simulations of silica. Peguiron, A., Ciacchi, L. C., Vita, A. D., Kermode, J. R., & Moras, G. Journal of Chemical Physics, American Institute of Physics, February, 2015. Paper abstract bibtex We report comparisons between energy-based quantum mechanics/molecular mechanics (QM/MM) and buffered force-based QM/MM simulations in silica. Local quantities–such as density of states, charges, forces, and geometries–calculated with both QM/MM approaches are compared to the results of full QM simulations. We find the length scale over which forces computed using a finite QM region converge to reference values obtained in full quantum-mechanical calculations is $∼$10 Å rather than the $∼$5 Å previously reported for covalent materials such as silicon. Electrostatic embedding of the QM region in the surrounding classical point charges gives only a minor contribution to the force convergence. While the energy-based approach provides accurate results in geometry optimizations of point defects, we find that the removal of large force errors at the QM/MM boundary provided by the buffered force-based scheme is necessary for accurate constrained geometry optimizations where Si?O bonds are elongated and for finite-temperature molecular dynamics simulations of crack propagation. Moreover, the buffered approach allows for more flexibility, since special-purpose QM/MM coupling terms that link QM and MM atoms are not required and the region that is treated at the QM level can be adaptively redefined during the course of a dynamical simulation.
@article{wrap66305,
volume = {142},
month = {February},
title = {Accuracy of buffered-force QM/MM simulations of silica},
author = {Anke Peguiron and Lucio Colombi Ciacchi and Alessandro De Vita and James R. Kermode and Gianpietro Moras},
publisher = {American Institute of Physics},
year = {2015},
journal = {Journal of Chemical Physics},
url = {https://wrap.warwick.ac.uk/66305/},
abstract = {We report comparisons between energy-based quantum mechanics/molecular mechanics (QM/MM) and buffered force-based QM/MM simulations in silica. Local quantities{--}such as density of states, charges, forces, and geometries{--}calculated with both QM/MM approaches are compared to the results of full QM simulations. We find the length scale over which forces computed using a finite QM region converge to reference values obtained in full quantum-mechanical calculations is {$\sim$}10 {\rA} rather than the {$\sim$}5 {\rA} previously reported for covalent materials such as silicon. Electrostatic embedding of the QM region in the surrounding classical point charges gives only a minor contribution to the force convergence. While the energy-based approach provides accurate results in geometry optimizations of point defects, we find that the removal of large force errors at the QM/MM boundary provided by the buffered force-based scheme is necessary for accurate constrained geometry optimizations where Si?O bonds are elongated and for finite-temperature molecular dynamics simulations of crack propagation. Moreover, the buffered approach allows for more flexibility, since special-purpose QM/MM coupling terms that link QM and MM atoms are not required and the region that is treated at the QM level can be adaptively redefined during the course of a dynamical simulation.}
}
Downloads: 0
{"_id":"MwxyX25eZsLAqqzX4","bibbaseid":"peguiron-ciacchi-vita-kermode-moras-accuracyofbufferedforceqmmmsimulationsofsilica-2015","author_short":["Peguiron, A.","Ciacchi, L. C.","Vita, A. D.","Kermode, J. R.","Moras, G."],"bibdata":{"bibtype":"article","type":"article","volume":"142","month":"February","title":"Accuracy of buffered-force QM/MM simulations of silica","author":[{"firstnames":["Anke"],"propositions":[],"lastnames":["Peguiron"],"suffixes":[]},{"firstnames":["Lucio","Colombi"],"propositions":[],"lastnames":["Ciacchi"],"suffixes":[]},{"firstnames":["Alessandro","De"],"propositions":[],"lastnames":["Vita"],"suffixes":[]},{"firstnames":["James","R."],"propositions":[],"lastnames":["Kermode"],"suffixes":[]},{"firstnames":["Gianpietro"],"propositions":[],"lastnames":["Moras"],"suffixes":[]}],"publisher":"American Institute of Physics","year":"2015","journal":"Journal of Chemical Physics","url":"https://wrap.warwick.ac.uk/66305/","abstract":"We report comparisons between energy-based quantum mechanics/molecular mechanics (QM/MM) and buffered force-based QM/MM simulations in silica. Local quantities–such as density of states, charges, forces, and geometries–calculated with both QM/MM approaches are compared to the results of full QM simulations. We find the length scale over which forces computed using a finite QM region converge to reference values obtained in full quantum-mechanical calculations is $∼$10 Å rather than the $∼$5 Å previously reported for covalent materials such as silicon. Electrostatic embedding of the QM region in the surrounding classical point charges gives only a minor contribution to the force convergence. While the energy-based approach provides accurate results in geometry optimizations of point defects, we find that the removal of large force errors at the QM/MM boundary provided by the buffered force-based scheme is necessary for accurate constrained geometry optimizations where Si?O bonds are elongated and for finite-temperature molecular dynamics simulations of crack propagation. Moreover, the buffered approach allows for more flexibility, since special-purpose QM/MM coupling terms that link QM and MM atoms are not required and the region that is treated at the QM level can be adaptively redefined during the course of a dynamical simulation.","bibtex":"@article{wrap66305,\n volume = {142},\n month = {February},\n title = {Accuracy of buffered-force QM/MM simulations of silica},\n author = {Anke Peguiron and Lucio Colombi Ciacchi and Alessandro De Vita and James R. Kermode and Gianpietro Moras},\n publisher = {American Institute of Physics},\n year = {2015},\n journal = {Journal of Chemical Physics},\n url = {https://wrap.warwick.ac.uk/66305/},\n abstract = {We report comparisons between energy-based quantum mechanics/molecular mechanics (QM/MM) and buffered force-based QM/MM simulations in silica. Local quantities{--}such as density of states, charges, forces, and geometries{--}calculated with both QM/MM approaches are compared to the results of full QM simulations. We find the length scale over which forces computed using a finite QM region converge to reference values obtained in full quantum-mechanical calculations is {$\\sim$}10 {\\rA} rather than the {$\\sim$}5 {\\rA} previously reported for covalent materials such as silicon. Electrostatic embedding of the QM region in the surrounding classical point charges gives only a minor contribution to the force convergence. While the energy-based approach provides accurate results in geometry optimizations of point defects, we find that the removal of large force errors at the QM/MM boundary provided by the buffered force-based scheme is necessary for accurate constrained geometry optimizations where Si?O bonds are elongated and for finite-temperature molecular dynamics simulations of crack propagation. Moreover, the buffered approach allows for more flexibility, since special-purpose QM/MM coupling terms that link QM and MM atoms are not required and the region that is treated at the QM level can be adaptively redefined during the course of a dynamical simulation.}\n}\n\n","author_short":["Peguiron, A.","Ciacchi, L. C.","Vita, A. D.","Kermode, J. R.","Moras, G."],"key":"wrap66305","id":"wrap66305","bibbaseid":"peguiron-ciacchi-vita-kermode-moras-accuracyofbufferedforceqmmmsimulationsofsilica-2015","role":"author","urls":{"Paper":"https://wrap.warwick.ac.uk/66305/"},"metadata":{"authorlinks":{}}},"bibtype":"article","biburl":"http://wrap.warwick.ac.uk/cgi/exportview/author_id/39508/BibTeX/39508.bib","dataSources":["mPSAr4TqWJWGXCQrN"],"keywords":[],"search_terms":["accuracy","buffered","force","simulations","silica","peguiron","ciacchi","vita","kermode","moras"],"title":"Accuracy of buffered-force QM/MM simulations of silica","year":2015}