The isotope effect of a single jump vacancy diffusion mechanism in a statically disordered lattice was investigated by Monte Carlo simulations. It was found that the isotope effect decreased significantly with increasing disorder. This effect was attributed to percolation processes and the resultant reduction in the effective space for the diffusing particle.

Small Isotope Effect of Diffusion in Disordered Structures. N.P.Lazarev, A.S.Bakai, C.Abromeit, V.Naundorf: Physical Review Letters, 2002, 88[4], 045502 (4pp)