Numerical Study of the Structural and Thermal Properties of Vitreous Silica

Abstract

We use classical molecular dynamics simulations to study both the structural modifications through the glass transition and the thermal conductivity k of a model silica glass. The first part is based on the Voronoï tessellation and we show that the structural freezing following upon the glass transition is noticeable in all the geometric characteristics of the Voronoï cells and a possible interpretation in terms of geometrical frustration is proposed.

In the second part we calculate k directly in the simulation box by using the standard equations of heat transport. The calculations have been done between 10 and 1000 Kelvin and the results are in good agreement with the experimental data at temperatures above 20 K. The plateau observed around 10 K can be accounted for by correcting our results taking into account finite size effects in a phenomenological way.