Diffusion and structure in liquid silica under pressure was investigated by a molecular dynamics model of 999 atoms with the inter-atomic potentials of van Beest, Kramer and van Santen. The simulation reveals that silica liquid was composed of the species SiO4, SiO5 and SiO6 with a fraction dependent on pressure. The density as well as volume of voids could be expressed as a linear function of the fraction of those species. Low-density liquid was mainly constructed of SiO4 and has a large number of O- and Si-voids and a large void tube. This tube contains most O-voids and was spread over the whole system. Anomalous diffusion behavior was observed.

Diffusion and Structure in Silica Liquid - a Molecular Dynamics Simulation. P.K.Hung, N.V.Hong, L.T.Vinh: Journal of Physics - Condensed Matter, 2007, 19[46], 466103 (12pp)