Term dependence of nondipole valence s-photoelectron angular distributions from half-filled shell atoms*

To date, nondipole photoelectron angular distributions from open-shell atoms have remained poorly studied because of their complexity in both experimental and theoretical studies. To remedy this situation, we have initiated a theoretical research program for studying nondipole effects in these atoms. The aim of this presentation is to demonstrate a dramatic dependence of nondipole valence s-photoelectron angular distributions on final state terms of the open-shell atom-remainder. It turns out that electron correlation affects these nondipole angular distributions crucially but much differently depending on a final state term of the residual ion. As a result, there are marked differences between nondipole contributions to the valence s-photoelectron angular distributions ``belonging'' to different final state terms of the ion-remainder. This is demonstrated by our calculations for the 4s photoelectrons from the Mn(3d$^{5}$4s$^{2}$,$^{6}S$) atom for the 4s,$^{5}S$ and 4s,$^{7}S$ final state terms of the ion-remainder. Calculations were performed in a ``spin-polarized'' random-phase-approximation with exchange (SP RPAE) framework.