Molecular dynamics simulation of the dynamics of supercooled silica

We present the results of a large-scale computer simulation of supercooled silica. We find that at high temperatures the diffusion constants show a non-Arrhenius temperature dependence, whereas at low temperature this dependence is compatible with an Arrhenius law. We demonstrate that at low temperatures the intermediate scattering function shows a two-step relaxation behaviour and that it obeys the time-temperature superposition principle. We also discuss the wave-vector dependence of the non-ergodicity parameter and the time and temperature dependences of the non-Gaussian parameter.