Determination of Concentration-Dependent Surface Diffusion Coefficients

Surface diffusion coefficients have been determined by several groups of investigators who have all assumed that the coefficient is independent of concentration. This however, is not a valid assumption in the case of atoms migrating over a surface. In certain cases, an appropriate\u27 change of variables reduces the general diffusion equation to an equation with a single independent variable, and allows one to obtain a solution involving the concentration- dependent diffusion coefficients. The atomic beam method offers a new experimental approach to the study of surface migration. From measurements of the concentration of potassium atoms migrating along a stainless steel surface, concentration-dependent surface diffusion coefficients are determined