Relaxation effects in inner-shell photoionization of Mg, Ca, and Sr

Total and partial photoionization cross sections have been calculated for all inner subshells of atomic magnesium, calcium, and strontium in the relativistic random-phase approximation, the relativistic random-phase approximation modified to include relaxation effects, and the relativistic random-phase approximation modified to include relaxation and Auger decay. Results of the three models are compared with Dirac-Hartree-Fock calculations and with semiempirical results so that the import of various many-body effects can be assessed. Branching ratios and photoelectron angular-distribution asymmetry parameters are also presented for np subshells. Substantial relaxation effects are noted for photoionization of $1s$ and $2s$ subshells.