Molecular-dynamics analysis of the structural properties of silica during cooling

The structural properties of SiO₂ liquid during cooling have been investigated by molecular dynamics simulations. The interatomic forces acting on the particles are calculated by the modified Tersoff potential parameters. The glass transition temperature and structural properties of the resulting SiO₂ system at various temperatures have been investigated. The fivefold coordinations of Si and threefold coordinations of O atoms were observed, and the coordination defects of system decrease with decreasing temperature up to 17 % at 300 K. The self-diffusion coefficients for Si and O atoms drop to almost zero below 3000 K. The structures were distorted at high temperatures, but very stable atomic network persisted up to high temperature in the liquid state.