Mechanical properties of silica glass predicted by a pair-wise potential in molecular dynamics simulations

• A smaller cutoff (e.g., 5.5 Å) gives better density of BKS silica glass.
• A larger cutoff (e.g., 10 Å) is needed to improve the mechanical properties.
• Compression of BKS silica glass is better described with a larger cutoff (e.g., 10 Å).

Pair-wise BKS potential for silica glass was modified by changing the short-range cutoff to improve the prediction of mechanical properties. Classical molecular dynamic (MD) simulations were carried out by using this modified potential and better prediction of mechanical properties at ambient conditions and their changes with pressure at room temperature were shown. It was further observed that there was no major change in structural properties when different short-range cutoffs were used to relax the glass. To better understand the contribution of structure to the mechanical properties, samples quenched under various cooling rates and one structure optimized in first principles calculations were used. It was seen that the improvement of structure has a less effect than improving the interaction potential in determining the mechanical properties of BKS silica glass. The strength and weakness of the BKS potential for silica glass was discussed.