Propagation of plane-wave vibrational excitations in disordered systems

The propagational behavior of vibrational plane waves in a disordered medium has been analyzed theoretically in the time and frequency domains and in terms of the final scattered state in momentum space. Numerical results have been obtained for a normal-mode analysis of models of vitreous silica constructed by molecular dynamics, and also for a simple model of a zigzag chain of atoms with force-constant disorder.