X-Ray Spectroscopic Data in Regard to the Electronic Energy Bands in Potassium and Sodium Chlorides

The wave-lengths of several lines in the $K\beta$ group of Cl in NaCl and KCl, and of K in KCl, have been measured in the secondary radiation from pressed blocks of the salts. The results are discussed in terms of the electronic energy bands in these crystals. It is shown that certain of the weaker lines arise from transitions of valence electrons belonging to one of the ions into a $K$ shell vacancy in the other ion. Some of the residual nondiagram lines seem to be related to the excited levels in irradiated crystals.