Abstract: Multi-body interaction and atomic charge transfer played essential roles in depicting the ionic-covalent bonds of Si—O systems. The limitations of 3-body terms in interatomic potentials for silica glass were analyzed according to molecular dynamics studies at high temperature, and it was found that pair-wise ionic potentials were better in simulating the microstructure evolution of silica glass than multi-body potentials. Moreover, the effects of atomic charge transfer on atomic self-diffusion were investigated, which showed that the activation temperature of atomic self-diffusion calculated with the Morse potential was lower than that calculated with the BKS potential due to the less atomic charge transfer in Morse potential. It was also found that the atomic self-diffusion coefficients calculated increased with the decrease in atomic charge transfer at the same temperature. Therefore, the pair-wise potentials with less atomic charge transfer should be in favor of investigating the dynamic properties of silica glass at high temperature.

Key words: Silica glass, High temperature, Molecular dynamics, Multi-body potential, Charge transfer