The auxiliary function which governed the temperature dependence of the small-polaron diffusion coefficient, D(T), was calculated with improved accuracy for impurities which occupied tetrahedral and octahedral interstitial sites in Ta, Nb and V. This function depended only upon the host crystal, and determined the shape of D versus T curves. The nature of the diffusing species entered only as a scaling factor and displacement of the Arrhenius plot of D(T). The calculation took account of the real vibrational modes of the host crystals, and used state-of-the-art integration techniques over the Brillouin zone to give very reliable and accurate results. Tables were provided for the interpretation of further experiments. As an example, diffusion data on H in Ta at temperatures ranging from 15 to 500K were analyzed on the basis of the quantum theory of diffusion and a 2-state model.

J.Rogan, M.Lagos: Physica Status Solidi B, 1994, 183[2], 375-82