Isotope effect in vacancy diffusion

Abstract
The experimental determination of correlation factors in diffusion in crystals is of great value in elucidating diffusion mechanisms. Schoen (1958) has recently proposed a method applicable to both metals and non-metals based on measurements of the relative diffusion rates of two different isotopes of the diffusing element. His analysis was based on an equation derived from an approximate expression for the correlation factor for vacancy diffusion. It is shown in the present paper that his basic equation is exact for all systems having at least two-fold rotational symmetry about the vacancy-solute jump directions.