Collective Excitations in Amorphous Ice

The paper presents the results of molecular dynamics simulating microscopic collective excitations in low-density amorphous ice, with the simulation being based on the monatomic ML-mW model of the intermolecular interaction potential. The calculated spectra of longitudinal $${{C}_{{\text{L}}}}(k,\omega )$$ and transverse $${{C}_{{\text{T}}}}(k,\omega )$$ current spectra have revealed the propagation of collective excitations of the longitudinal and transverse polarizations in amorphous ice within a wide range of wavenumbers. The region of mixing the longitudinal and transverse collective modes in low-density amorphous ice has been found. It has been shown that, in terms of the dispersion law of transverse acoustic-like modes, the temperature dependence of gap width kgap is described by a linear dependence.