Effective single-particle potential for photoabsorption of open-shell atoms

Abstract
A method to obtain an effective single-particle potential for the photoabsorption of open-shell atoms is discussed and applied to the calculation of the photoionization cross section of neutral chlorine. The potential includes, in an approximate way, the effects of interaction among many final channels. For chlorine, the results are in very good agreement with elaborate many-body calculations except for the failure to describe resonance structure.