Single-Crystal Orientation Effects inKX-Ray Absorption Spectra of Ge

The extended fine structure on the short-wavelength side of the $K$ x-ray absorption edge of a thin single crystal of Ge has been studied for three different orientations of the crystal. Although the polarization was only 7%, shifts in the positions of the structure features were observed between 75 ev and 280 ev from the edge. These shifts are tabulated and discussed. A careful comparison of the absorption of a single crystal of Ge and a single crystal of an alloy of 7% Si in Ge has been made to 60 ev from the Ge $K$-edge. Significant changes in the structure were noted as well as a probable shift in the position of the edge.