Development of Empirical Potentials for Amorphous Silica

Amorphous silica (SiO2) is of great importance in geoscience, mineralogy and is also a raw material in industry. Its structure is characterized as a continuous network of SiO4 tetrahedra.The microscopic properties of silica can be understood using classical molecular dynamics simulations where the interactions are modeled by an effective potential that does not take into account quantum effects. In this work, we propose a new methodology to parameterize such a potential for silica.This potential is compared to the BKS potential. Our new potential gives a better description of amorphous silica than the BKS one: pair correlation functions, angular distribution functions, structure factors and pressure/density are improved. The vibrational spectrum of vitreous silica is in good agreement with experiments. Our new potential was shown to be also transferable: The equilibrium geometry and the elastic constants of quartz are accurately predicted.