Photoionization of atoms with half-filled shells

The method of random phases with exchange is generalized to take into account many-electron correlations in atoms with half-filled shells. The effect of correlations on photoionization cross sections and angular distributions of photoelectrons from chromium, manganese, and technetium atoms in the region of the 3p- and 4p-thresholds is investigated. It is shown that this region is dominated by a large peak of autoionization origin. The outer-shell level energies are determined for the manganese atom with allowance for many-electron correlations. Results of these calculations are in good agreement with experiment