On force fields for molecular dynamics simulations of crystalline silica

Abstract

This paper reviews and examines interatomic potentials or force fields for molecular dynamics (MD) simulation of crystalline silica. The investigated potentials are the BKS, Pedone, Munetoh, TTAM, and CHIK. The calculated values of the lattice constants, density, radial and bond-angle distribution functions, equations of state, and phase transitions using different potentials are compared to experimental values for polymorphs of silica: quartz, cristobalite, coesite, and stishovite. Simulation results with the BKS potential accurately predict the experimental measurements to within 2%, and converge within a reasonable timeframe on an average workstation. The Pedone potential, also parameterized for other metallic oxides, computationally is slightly more expensive and is not as accurate. The simulations with both the CHIK and TTAM potentials are less accurate than with the BKS potential for modeling silica over the entire range of the phase diagram. The simulations with the Munetoh potential are by far the cheapest in terms of the modest computational requirements, but unsuitable for modeling crystalline silica. It could not produce the nature of the α–β and I–II phase transitions in quartz or the equation of state for stishovite silica, and the predicted structural properties sometimes differ from experimental values by more than 10%.