Diffusion in a 2-dimensional stoichiometric ordered alloy model was considered by using Monte Carlo simulations and analysis. The results were used to determine how the correlation factor for diffusion, as found from an isotope effect experiment, was related to the actual correlation factor (with all jumps included) and to the correlation factor for effective diffusion via the 6-jump mechanism. It was shown that the apparent correlation factor which was deduced from an isotope-effect experiment could deviate markedly from the actual correlation factor. It extrapolated to precisely that for the 6-jump cycle when the long-range order parameter approached unity. This clarified the relationships between various correlation factors in ordered alloys when inter-sublattice jumps predominated.

Diffusion Correlation Effects and the Isotope Effect in Intermetallic Compounds. I.V.Belova, G.E.Murch: Philosophical Magazine A, 2000, 80[9], 2073-81