Correlation and relativistic effects on the photoionization of confined atoms

A study of the combined effects of correlation, confinement and relativistic effects on the photoionization of the outer ns subshells of the alkaline-earth-metal atoms, Mg, Ca, Sr and Ba has been performed with particular emphasis on the Cooper minima using the relativistic-random-phase approximation (RRPA) methodology. It is found that the response of the Cooper minima to these various effects can be rather different behavior for the various atoms considered. On the other hand, relativistic effects were found to be essentially obliterated by confinement, in all cases. The situations are analyzed in detail and qualitative understanding of most of the phenomenology is presented. © 2007 The American Physical Society.