Atomic photoionization calculations using local continuum exchange approximations

Results using some previous models for atomic photoionization were calculated using all four forms of the dipole operator: length, velocity, acceleration based on the initial-state potential gradient, and acceleration based on the final-state potential gradient. Calculations were performed on one or more subshells of six atoms. In no case did a previous result agree better with the corresponding Hartree-Fock result than did the Hartree-Slater calculation. The four operators results within each subshell are compared in order to understand this. It is concluded that open-shell interactions must be taken into account in model exchange potentials for photoionization. An untested implication is that the success with electron - molecule scattering calculations is due to the restriction to electron closed-shell cases. 12 references