Theory of deep impurity levels in CuCl

The theory of deep impurity levels is extended to semiconductors with $d$ electrons. The major chemical trends are predicted for a large number of substitutional impurities in CuCl. Deep levels are found for S and Se impurities on the Cl site, but not for Ag or Au on the Cu site, in agreement with experiment. The theory also predicts no deep level for isolated O on the Cl site, thus supporting the conclusion that the observed O-related defect is not a simple substitutional impurity.