Closing of Coster–Kronig transitions in multiply ionised gold atoms

Abstract

The paper discusses the effect of closing of L- and M-shell Coster–Kronig (CK) transitions in multiply ionised Au atoms, for which the selected CK transitions become energetically forbidden. This effect plays an important role when the Coster–Kronig energy for single-hole configuration is relatively low, being comparable with a change of the electronic binding energies in multiply ionised atom. We show, by using a simplified model, that for gold the effect of closing of CK transitions occurs for strong L1–L3M4,5 transition for the L1-subshell as well as the M3–M5N6,7 and M4–M5O3,4 CK transitions for the M3- and M4-subshell, respectively. We demonstrate that the discussed effect of closing CK transitions substantially changes the X-ray fluorescence and Coster–Kronig yields and thus has to be considered in interpretation of X-rays excited by heavy ion impact.