COLLECTIVE EXCITATIONS IN AMORPHOUS ICE

The paper presents the results of a study of microscopic collective excitations in low-density amorphous ice obtained by molecular dynamics simulation based on the monatomic ML-mW model of the intermolecular interaction potential. The calculated spectra of longitudinal C(k, ω) and transverse C(k, ω) currents reveal the presence of propagating collective excitations of longitudinal and transverse polarizations in amorphous ice for a wide range of wavenumbers. The region of mixing of longitudinal and transverse collective modes in low-density amorphous ice is established. It is shown that the temperature dependence of the gap width k in the dispersion law of transverse acoustic-like modes is described by a linear dependence.