Bond-order reactive force fields for molecular dynamics simulations of crystalline silica

This paper investigates the applicability of the bond-order, variable-charge (BOVC) force fields of the Charge-Optimized Many-Body (COMB10), ReaxFF(SiO)(H2O) , and ReaxFF(SiO)(GSI) , for molecular dynamics (MD) simulations of crystalline SiO2. The calculated lattice constants and densities of the four SiO2 polymorphs, quartz, cristobalite, coesite, and stishovite, are compared to experimental values. Additionally, the calculated pair distribution and bond-angle distribution functions and the alpha-beta transition for quartz, the most stable low-energy polymorph, are compared to experimental results. The simulations with the COMB10 force field accurately predict the properties of the SiO2 polymorphs, except the alpha-cristobalite, and the quartz alpha-beta transition. The results with ReaxFF(SiO)(H2O) and ReaxFF(SiO)(GSI) accurately predict the properties of the SiO2 polymorphs, except the stishovite, but those with ReaxFF(SiO)(H2O) inaccurately predict the quartz alpha-beta transition. (C) 2015 Elsevier B.V. All rights reserved.