Random-phase approximation with exchange for inner-shell electron transitions II: Effects of inter-shell correlations*

A random-phase approximation with exchange (RPAE) method, which allows the inclusion of both the intra-shell correlations and the inter-shell correlations in photoionization calculations, has been developed for open-shell atoms (ions), such as I, Xe$^+$, and I$^+$. The equations for all types of matrix elements have been derived and implimented in a computer code. The program has been used to study the effects of inter-shell correlations on the Xe$^+$ 5$s$, 5$p$ and $4d$ photoionization processes, which are found to increase dramatically the cross sections for the Xe$^+$ $5s$ and $5p$ eletrons.