Velocity Analysis of Potassium Atoms Scattered by Magnesium Oxide

Abstract

A beam of potassium atoms is scattered by an MgO crystal and the magnetic velocity analyzer used to determine the distribution in velocity of the scattered atoms. The resulting velocity spectrum agrees very well with that calculated on the assumption of a Maxwell distribution characteristic of the temperature of the crystal although the crystal temperature was varied over a wide range. A rough study made of the spatial distribution of the scattered atoms showed no evidence of specular reflection or of diffraction but merely random or cosine scattering. The scattering process appears to be one of adsorption and re-evaporation.