The dynamical structure factor in topologically disordered systems

A computation of the dynamical structure factor of topologically disordered systems, where the disorder can be described in terms of Euclidean random matrices, is presented. Among others, structural glasses and supercooled li quids belong to that class of systems. The computation describes their rele vant spectral features in the region of the high frequency sound. The analy tical results are tested with numerical simulations and are found to be in very good agreement with them. Our results may explain the findings of inel astic x-ray scattering experiments in various glassy systems. (C) 2001 Amer ican Institute of Physics.