Compton Scattering and Electron Momentum Density in Beryllium

Abstract

Compton-scattered x-ray spectra were measured for three orientations of a beryllium single crystal. The reduced profiles were analyzed in terms of the electron momentum distribution. Observed anisotropies can be explained qualitatively in terms of the geometry of the Fermi surface and are in qualitative agreement with earlier positron and x-ray data. The present results show high-momentum components among the valence electrons which are not revealed in the positron experiment nor accounted for by available calculations. In the process of reducing the data to obtain the momentum distribution of the valence electrons, detailed consideration was given to the effects of binding upon the Compton scattering by the core electrons.