Molecular dynamics simulation of binary hard sphere colloids near the glass transition

Abstract

This study reports on molecular dynamics simulations of concentrated binary hard sphere colloids near the glass transition. We present the three-dimensional mean square displacements for systems that increase in density, into the glass transition region. The molecular dynamics simulations probe wider time scales than the experimentally assessable range. They cover the short time scale that corresponds to ballistic motion, the intermediate scale that corresponds to caged Brownian motion, and the long time diffusion described by the Einstein–Smoluchowski limit. We report results for α₂, the non-Gaussian parameter, which captures the details of the mean square displacements around the time that, on average, rearrangements of the particle cages occur. The dynamic temporal correlations were examined in terms of the four point susceptibility. The implications for ageing are also discussed.