Relationship between the dynamic properties of 1h ice and xenon hydrate and the interplay of intramolecular and intermolecular vibrations

A new approach was used to simulate vibration spectra of 1h ice and xenon hydrate in the range 0-4000 cm(-1), which encompasses both intramolecular and intermolecular vibrations. This approach, based on. the lattice dynamics method, enables full spectra to be obtained for molecular crystals with allowance for the coupling of intramolecular and lattice vibrations. It is shown that consideration of this coupling leads to splitting of the peaks of intramolecular vibrations and to a significant change in the spectrum in the range of translation and libration molecular vibrations, which agrees qualitatively with experimental results.