Photoionization of Some Closed-shell Atoms and Ions

Dipole-allowed single photoionization of some closed shell atoms and ions has been investigated in the relativistic random-phase approximation (RRPA). Application of relativistic-multichannel quantum defect theory (RMQDT) is made together with RRPA to analyse autoionizing resonances. Analysis points to the importance of interchannel coupling in high energy photoionization and reveals various degeneracies in relativistic atomic spectra to influence the low energy dynamics. Interesting threshold behavior in photoelectron spin polarization has been seen. Prospective future studies have been indicated