Surface Migration of Potassium on Metallic Surfaces

Recent atomic beam scattering experiments have given evidence of migration of neutral atoms along metallic surfaces. Evaporation of the atoms from the oven surface acts as a wide effective source, leading to undesirable results in the scattering measurements. Little is known of the basic mechanism of this type of surface migration. A series of experiments were performed to investigate in greater detail various properties of surface migration by observing the movement of neutral potassium atoms over a metallic surface. From the measurements of the spatial and temporal variations of the surface concentration, the migration rate was determined and thus the diffusion coefficient was calculated. By noting the effect of temperature on the diffusion coefficient the activation energy for the migration of potassium on a stainless steel surface was obtained