Dynamical diagnostics for the glass transition in soft-sphere alloys

Abstract

The structural slowing down in a binary alloy of soft spheres near the fluid-glass transition has been investigated by extensive molecular dynamics simulations. An attempt is made to characterise the transition on the basis of r- and k-space representations of the incoherent and coherent parts of the density autocorrelation functions. A careful analysis of the Van Hove functions allows the authors to put forward two novel diagnostics of the underlying 'ideal' glass transition, which yield the same value of the critical glass transition temperature. The latter appears to be independent of the mass ratio of the two species in the mixture. The damping of the longitudinal sound mode at the longest accessible wavelength appears to be surprisingly independent of temperature, while the damping of the corresponding transverse sound mode decreases significantly as the temperature is lowered.