Relaxation effects in 2p photoionization of Ar isonuclear sequence

Abstract

The 2p photoionization cross sections of Ar, Ar6+ and Ar8+ have been investigated by the multiconfiguration Dirac-Fock method. Our results show excellent agreement with the previous measurements and calculations, the relaxation is not so important for inner subshells of neutral Ar and all subshells of Ar6+ and Ar8+ as generally accepted. In unrelaxed calculation, it is known that the inner-shell cross sections are essentially unchanged upon the presence or absence of outer electrons except for a shift in the corresponding thresholds. Specifically, the present results show that this is not entirely true, i.e., non-neglectable influence of the removal of outer electrons on the 2p cross sections is observed even when the relaxation effects are not considered, especially in energy region near the thresholds.