Molecular Dynamics Computer Simulation of the Dynamics of Supercooled Silica

TL;DR

This paper reports large-scale molecular dynamics simulations of supercooled silica, revealing temperature-dependent diffusion behavior, two-step relaxation, and non-Gaussian dynamics, advancing understanding of silica's glassy state.

Contribution

It provides detailed simulation data on supercooled silica's dynamics, including temperature dependence of diffusion and relaxation processes, highlighting behaviors at different temperature regimes.

Findings

Diffusion constants show non-Arrhenius behavior at high T

At low T, diffusion follows Arrhenius law

Intermediate scattering function exhibits two-step relaxation

Abstract

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 also compatible with an Arrhenius law. We demonstrate that at low temperatures the intermediate scattering function shows a two-step relaxation behavior and that it obeys the time temperature superposition principle. We also discuss the wave-vector dependence of the nonergodicity parameter and the time and temperature dependence of the non-Gaussian parameter.