Selecting reliable interatomic potentials for classical molecular dynamics simulations of glasses: The case of amorphous SiO2

This paper presents an approach to judge the quality of classical interatomic potentials used in molecular dynamics simulations of glasses. The static structure and dynamical properties of amorphous SiO2 were simulated by classical molecular dynamics using a series of well known interatomic potentials. Theoretical X-ray and neutron structure factors and effective neutron-weighted vibrational density of states of amorphous SiO2 were computed from the obtained atomistic configurations and quantitatively compared to experimental results. The interatomic potential which best reproduced the experimental X-ray and neutron scattering data severely failed to reproduce the experimental vibrational density of states of amorphous SiO2. It is found that only the potential developed by van Beest, Kramer, and van Santen (BKS) was able to adequately reproduce both static structure and dynamical properties of amorphous SiO2. Thus, the fact that an interatomic potential is able to properly reproduce static structures of amorphous systems should not be considered as a basis to use this potential to simulate other properties of these systems.