The dipole nuclear magnetic relaxation rate which was associated with the hopping diffusion of interstitial H atoms in a disordered alloy was calculated by using Monte Carlo methods. The main features of the model were that the atoms hopped on a spatially disordered array of traps, and the trapping energy varied from trap to trap so that the diffusion of H was characterized by a distribution of jump rates. The effective jump rate from a trap was assumed to have an Arrhenius dependence upon the temperature, and this caused the distribution of jump rates to depend upon the temperature. The method explored the manner in which this dependence affected the mean jump rate, as well as providing a means for calculating the relaxation as a function of the Larmor frequency and the temperature. The mean jump rate was found to deviate from Arrhenius behavior in a manner that depended upon the concentration of H nuclear spins. At a given temperature, the characteristic peak in the relaxation rate (which occurred in ordered solids when the product of the average jump rate and the Larmor frequency was approximately equal to unity) was broadened, became asymmetrical and was shifted in frequency by the presence of the jump rate distribution. The broadening was found to be less apparent when the relaxation rate was calculated as a function of temperature. However, the asymmetry remained.

H.Lu, J.M.Titman, R.L.Havill: Journal of Physics - Condensed Matter, 1995, 7[38], 7501-16