STRUCTURE AND STRUCTURE RELAXATION

A discrete-dynamics model, which is specified solely in terms of a sys tem's equilibrium structure, is defined for the density correlators of a simple fluid. This model yields results for the evolution of glassy dynamics which are identical with the ones obtained from the mode-cou pling theory for ideal liquid-glass transitions. The decay of density fluctuations outside the transient regime is shown to be given by a su perposition of Debye processes. The concept of structural relaxation i s given a precise meaning. It is proven that the long-time part of the mode-coupling theory solutions is structural relaxation, while the tr ansient motion merely determines an overall time scale for the glassy dynamics. (C) 1998 Elsevier Science B.V. All rights reserved.