Diffuse X-ray scattering measurements of dissolved H were carried out at room temperature. It was found that the application of uniaxial stresses which were below the elastic limit led to a transformation of all of the H atoms from 1T to 4T states. Each H atom was delocalized over 4 neighboring T sites by tunnelling. The diffusion of 4T H, under an external stress applied in a [111]-type direction, was measured at 200 to 340K. The diffusion results could be described by an Arrhenius relationship:

D (cm2/s) = 0.0016 exp[-0.006(eV)/kT]

Superdiffusion of 4T-Hydrogen in Vanadium. T.Suzuki, H.Namazue, S.Koike, H.Hayakawa: Physical Review Letters, 1983, 51[9], 798-803

Table 179

Parameters for H Diffusion in VHx