Low-frequency vibrations and molecular motions of H2O molecules in [Ni(H2O)6](ClO4)2 and in [Ni(D2O)6](ClO4)2 studied with neutron scattering methods

The results of simultaneous investigations of neutron powder diffraction and inelastic incoherent neutron scattering performed at the IBR-2 pulsed reactor of the JINR in Dubna are presented for [Ni(H2O)6](ClO4)2 and for [Ni(D2O)6](ClO4)2. The emphasis is on the dynamics. Some evidence of molecular motions in the sample was obtained. A proton orientational glass, showing the additional density of states over the parabolic dependence of the G(ω) of ordered crystals, was obtained at low temperatures when cooling the sample below room temperature