ON THE ORIGIN OF THE LOW-FREQUENCY EXCITATIONS IN GLASSY SELENIUM

The microscopic low-frequency dynamics of glassy selenium is investigated by means of the concurrent use of neutron inelastic scattering and computer simulations. A separation of the dynamic response in terms of intra- and interchain processes is achieved from the analysis of the simulation results. The low-frequency peak in the dynamic structure factor S(Q, E) as well as the tail of the vibrational density of states Z(E) are then shown to be originated mostly by interchain interactions. The implications of these findings for the anomalous thermal behaviour of glasses are finally discussed.