Inelastic neutron scattering study of the (O{sub 4}H{sub 4}) substitution in garnet

Inelastic scattering data have been collected at incident neutron energies of 50, 150, 300 and 600 meV for hydrogarnet [Sr{sub 3}Al{sub 2}(O{sub 4}H{sub 4}){sub 3}], a model compound for silicate hydrogarents found in the Earth`s crust and mantle. The vibrational spectrum is characterized by a relatively sharp O-H stretch at {approximately}460 meV, which is consistent with the weak O...H bond ({approximately}2.65 {angstrom}) and other complex features in the 20-100 meV region. The mode assignment for isostructural grosslar and the infrared spectra for hydrogarnet were used as a basis for the intreperation of many of the neutron spectral features