Vacancy-assisted tracer diffusion: response at small vacancy concentration

Abstract
Classical rate equations for the diffusional response of a tracer atom are solved exactly in the limit of small vacancy concentration. Analytical results valid in the small-wavevector, small-frequency limit are obtained which lead to exact results for the vacancy-assisted tracer diffusion coefficient. Numerical results for the dynamical correlation factor, as well as the incoherent response function, are given for cubic lattices over a wide range of frequencies and a variety of wavevectors.