Measurements of the diffusion coefficient of ${}_{}{}^{113}{}_{}{}^{}\mathrm{Sn}$, ${}_{}{}^{124}{}_{}{}^{}\mathrm{Sb}$, ${}_{}{}^{110m}{}_{}{}^{}\mathrm{Ag}$, and ${}_{}{}^{195}{}_{}{}^{}\mathrm{Au}$ in liquid Sn have been made using a shear cell assembly which provides accurate data. The experimental diffusion coefficient is given by $D_i=C{D}_i^E$, where $D_i^E$ is obtained using Enskog's theory and $C$ is a correction factor accounting for dynamical effects. $C$ is strongly dependent on the density of the fluid and on the relative mass and size of the solute with respect to the solvent. The data show that (i) the density effects in self-diffusion are qualitatively in good agreement with molecular-dynamics calculations; (ii) for impurity diffusion, $C$ decreases with the mass of the solute, whatever the density, as predicted by molecular-dynamics (MD) calculations; (iii) size effects on $C$ are in agreement with MD calculations for impurities larger than the solvent; and (iv) Ag and Au solutes exhibit anomalously large values of $C$ which may be due to valence effects.

• Received 21 November 1979

DOI:https://doi.org/10.1103/PhysRevB.21.5447