The dependence of the diffusivity of interstitial atoms, in a particle density gradient, was computed as a function of the interstitial atom concentration and temperature. The calculation method involved the use of a combination of absolute rate theory and cumulant expansion techniques. It was found that the presence of the gradient resulted in the appearance of so-called skewing effects which caused the diffusivity to increase, with the interstitial atom concentration, more rapidly than did the diffusivity which was measured using interstitial tracers in the absence of a density gradient.

R.B.McLellan: Acta Materialia, 1997, 45[1], 99-103