Molecular-dynamics study of the glass transition in a binary soft-sphere model

Molecular-dynamics simulations have been carried out on a ``soft-sphere'' model for binary alloys quenched into supercooled states. The main emphasis of this work is on the dynamic characterization of the glass transition. In the vicinity of the glass transition jump motions of atoms are dominant for the diffusion processes, the mean-square displacement exhibits a non-t-linear behavior, sometimes called a subdiffusive behavior, and the self-parts of the density autocorrelation functions are well fitted by ``stretched exponential'' function. The non-Gaussian parameter as a function of time has a large maximum, and the product of the maximum value and the corresponding time increases sharply as it approaches the glass transition. It is shown that all these anomalous characteristic properties are in good agreement with the predictions of the trapping diffusion theory.