The lattice migration of interstitials of arbitrary mass was studied; assuming that the interstitial concentration was small. An expression for the transition rate was obtained which depended upon the interstitial concentration and allowed for the frequency spectrum of a defective crystal. This was done within the framework of the small-polaron formalism, while avoiding the adiabatic approximation. The effect of local modes upon interstitial jumps was considered, and an isotopic dependence was noted. It was shown that, for a limiting case in which the transition rate was determined by the Arrhenius dependence, the rate was proportional to M-½, where M was the mass of the interstitial.

G.L.Buchbinder: Physics Letters A, 1995, 209[1-2], 113-7