Hydrogen Vibrational Excitation Spectra of CaF<SUB>2</SUB>-Type Metal Hydrides Synthesized from Ti-Based BCC Solid Solution Alloys

Abstract

Hydrogen vibrational excitation was studied for CaF 2 -type metal hydrides synthesized from Ti-based BCC solid solution alloys using inelastic incoherent neutron scattering (IINS). Ti 1:0 V 1:1 Mn 0:9 H 4:5 and Ti 0:7 V 1:2 Cr 1:1 H 4:8 showed IINS spectra similar to that reported for TiH 2 . The first three peaks were isolated but the higher excitation peaks were not clear. Analysis of the spectra using curve-fitting with Gauss functions revealed that the hydrogen vibration of Ti 1:0 V 1:1 Mn 0:9 H 4:5 is harmonic but that of the Ti 0:7 V 1:2 Cr 1:1 H 4:8 is deviated from harmonic, which reflects a trumpet-type potential. The relation between metal-hydrogen distance and vibrational excitation energy for the above two hydrides and Ti 1:1 Cr 1:4 Mo 0:3 H $5 was compared with a series of CaF 2 -type binary metal hydrides. All the hydrides of the Ti-based alloys had lower vibrational excitation energies than the binary metal hydrides for the corresponding metal-hydrogen distances.