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Inelastic neutron scattering (INS) measurements of the vibrational frequencies in δ-Zr hydride containing uranium, ZrH 1.6 U 0.32 , have been performed in the range of high temperatures (between 293 and 973 K) at the DIN-2PI time-of-flight spectrometer at the IBR-2 pulsed reactor of JINR, Dubna. From the temperature dependence of the generalized vibrational density of states (GVDS), information on the H potential has been obtained. Also the high frequency limit of lattice vibrations as well as the frequency of optical vibrations have been studied as functions of temperature. Starting from basic properties, the main thermodynamic functions, the characteristic Debye and Einstein temperatures and the total specific heat have been derived.

The vibrational frequencies of D in δ and e deuterides of Zr have been measured by inelastic neutron scattering. From the experimental data analyzed in terms of the generalized vibrational density of states new information on the H(D) potential in Zr have been obtained. Performing an accurate analysis of the high energy range of scattering spectra, the distribution of D atoms on the available interstitial sites in fcc and fct Zr lattices has been studied.

The changes of the dynamic properties of the zirconium lattice at transition from pure metal to different hydride and deuteride phases have been studied by investigating the generalized vibrational density of states (GVDS) or Zr, ZrH 1.6 , ZrD 1.6 , ZrH 2 , ZrD 2 and ZrH 1.6 U 0.32 in the region of the host lattice modes. The spectra obtained from inelastic neutron scattering (INS) measurements have been analysed in terms of the classical Debye model. The dependence of the high-frequency limit of lattice vibrations to different regular structures of zirconium atoms and its correlation with the main thermodynamic quantities, lattice specific heat C V and Debye temperature θ D have been reported.

The dynamic structure factor $S(Q,\ensuremath{\omega})$ for lead fluoride ${\mathrm{PbF}}_{2}$ in the normal and the superionic states at $T=293$ and 823 K has been investigated by cold neutron scattering. In the superionic state on a constant Q scale, two symmetrical peaks at low energies over a limited range of wave-vector transfers are observed. This structure is similar to the long-wavelength collective excitations (Brillouin doublet) specific to some liquid metals. Such an observation could support the idea of liquidlike behavior at the level of the anion sublattice in the superionic state. However, the energies of these excitations are about one order of magnitude smaller and the corresponding Q values are rather high compared to those of the collective modes observed in the simple classical liquids. Therefore these excitations are of different nature from those characteristic for a classical liquid.

The inelastic neutron scattering (INS) on ZrHx systems (x=0.38, 0.52 and 0.80) revealed low-frequency excitations located within the energy range 2–10 meV. Besides the lattice vibrations specific to α-HCP metallic Zr and γ-FCO Zr hydride, the fine structure of these excitations is clearly observed. The origin of the new observed peaks is not very clear but a proton tunneling or a resonance effect in α-Zr lattice could be taken into account.