Hydrogen storage is one of the most important technological issues to be resolved in the move towards a future sustainable hydrogen-based economy. We would like to gain further understanding the nature of the hydrogen diffusion, it¿s activation energy and also the geometry of the binding sites within two titanium-chromium-vanadium-molybdenum alloys, Ti10Cr10V75Mo5 and Ti25Cr50V20Mo5, as a function of hydrogen pressure and hydrogen loading / unloading (cycling) to determine the reasons for hydrogen sequestration and the deterioration of performance during cycling. We therefore request 8 days on LET/IRIS to complement inelastic neutron scattering data obtained on TOSCA and structural data obtained on GEM which indicate high hydrogen mobility at low loadings.