J. Phys. Colloques 28 (1967) C1-26-C1-33
ÉTUDE DES MODES DE VIBRATIONS LOCALISÉES DE L'HYDROGÈNE DANS L'HYDRURE DE VANADIUM PAR DIFFUSION INÉLASTIQUE DES NEUTRONS FROIDSW. KLEY, J. PERETTI, R. RUBIN and G. VERDAN
Département de Physique des Réacteurs, Service de Physique Neutronique Expérimentale, Euratom C. C. R., Ispra, Varese, Italie.
The scattering of cold neutrons from VHx, NbHx, and PdHx systems was measured at low hydrogen concentrations. The difference between the normalized intensity of the « hydrogen system », and that of the pure host lattice, gives the neutron scattering distribution of the « hydrogen probe » in the host lattice. These intensity distributions show the expected high energy « local modes » of the hydrogen impurity well above the maximum frequency of the host lattice. For VHx and NbHx in the α phase, a low energy neutron distribution of a few meV is also observed, close to the energy of the impinging neutrons. Apart from a certain distortion near the maximum host lattice frequency, in addition the host lattice frequency distribution can be « seen » through the hydrogen « band modes ». For Nb, two pronounced peaks are found at energy transfers of 25.9 and 18.3 meV. They agree reasonably well with recent calculations of the frequency distribution of Nb.