In order to clarify the nature of an unusual low-temperature H motion in this alloy, high-resolution quasi-elastic neutron scattering measurements of V2TaH0.6 were carried out at temperatures ranging from 10 to 300K. The results confirmed the occurrence of localized H motions with a hopping rate which was of the order of 109/s at 90K. The temperature dependence of the hopping rate appeared to be non-Arrhenius. The behavior of the elastic incoherent structure factor was consistent with models which posited H jumps between 3 or 6 sites on a circle with a radius of about 0.11nm.

A.V.Skripov, J.C.Cook, C.Karmonik, R.Hempelmann: Journal of Physics - Condensed Matter, 1996, 8[23], L319-24