High-precision Monte Carlo simulations were used to investigate tracer diffusion kinetics for diffusion via divacancies in body-centered cubic lattices. The mechanisms originally identified by Mehrer were assumed, in which the divacancy could move by nearest-neighbour jumps with stable first-nearest neighbour, second-nearest neighbour and fourth-nearest neighbour configurations of the divacancy. The tracer correlation factor and the so-called impurity-form correlation factor were found to be some 4 to 6% lower than those found by using the matrix method. Tracer diffusion data and isotope effects for Na were reconsidered in terms of monovacancy and divacancy contributions. The main result was an upwards adjustment, from 0.55 to 0.61, of the ΔK kinetic factor for divacancies.

Diffusion Kinetics for Divacancies in the BCC Lattice. I.V.Belova, D.S.Gentle, G.E.Murch: Philosophical Magazine Letters, 2002, 82[1], 37-41