The phonon-activated diffusion of an interstitial impurity in a 1-dimensional cosine potential was analyzed by using the Langevin continuous diffusion model and the Fokker-Planck jump-diffusion equations. The jump-rate, jump-length and diffusion coefficient were calculated as a function of temperature. There were differences between the results of the 2 analyses, and it was therefore unclear as to what extent the 2 models were equivalent.

Diffusion in Periodic Potential Langevin versus Fokker-Planck Equation Approach. B.Kozarzewski: Acta Physica Polonica B, 1998, 29[3], 513-27