The migration of H and D was studied by monitoring a relaxation process which was related to long-range diffusion. It was found that the results, at 270 to 560K, could be described by:

H:     D (cm2/s) = 5.4 x 10-4 exp[-0.110(eV)/kT]

D:     D (cm2/s) = 5.6 x 10-4 exp[-0.135(eV)/kT]

Relaxation Process Due to Long-Range Diffusion of Hydrogen and Deuterium in Niobium. G.Schaumann, J.Volkl, G.Alefeld: Physical Review Letters, 1968, 21[13], 891-3