MOLECULAR-DYNAMICS SIMULATION OF ALPHA-CRISTOBALITE AND BETA-CRISTOBALITE

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