THE LATTICE-DYNAMICS OF CLATHRATE HYDRATES - AN INCOHERENT INELASTIC NEUTRON-SCATTERING STUDY

The vibrational densities of states in the lattice translation region below 130 cm(-1) (3 THz) for structure I xenon hydrate and structure I I krypton hydrate have been determined from incoherent inelastic neutr on scattering experiments. The main features in the lattice vibrations are found to shift to higher frequencies when compared to ice I-h. Th e shift is due to repulsive interactions between the water molecules a nd the guests which help to stabilize the hydrate structure. The exper imental observation is in goad accord with that predicted from earlier molecular dynamics calculations.