Isotope Effect in Intermetallic Diffusion

Abstract

Ten measurements of the isotope effect for diffusion of ${\mathrm{Fe}}^{55}$ and ${\mathrm{Fe}}^{59}$ in pure single crystals of silver and copper have been made over approximately a 300°C temperature interval below the melting point. The measured isotope effect was found to be about $\frac{2}{3}$, significantly less than the value of unity expected from conventional reaction rate theory.