X-Ray Absorption Fine Structure with Polarized X-Rays

The fine structure on the short wavelength side of the $K$ x-ray absorption edge of Cl in single crystals of NaCl and KCl has been studied with polarized x-rays in a vacuum double-crystal spectrometer. The structure was obtained when the main direction of ejection of photoelectrons was perpendicular to a set of 100 planes and again when perpendicular to 110 planes. One significant difference in structure was noted for the two different directions of ejection in the case of NaCl.