Molecular dynamics simulation of alpha - and beta -cristobalite

Abstract
A molecular dynamics simulation of the alpha - and beta -phases of cristobalite has been performed. The simulated beta -phase was found to be much more disordered than the alpha -phase, in agreement with evidence from many experimental techniques. The nature of the disorder was found to be dynamic, in agreement with results from many experimental techniques, but no distinct domains were detected. The results are in agreement with the rigid unit mode (RUM) model of framework structures, and recent inelastic measurements.