Photoionisation process in the 5d, 6s and 6p shells of atomic lead and the 4d shell of atomic tin

Abstract

Photoionisation processes in the 5d, 6s and 6p shells of atomic lead and the 4d shell of atomic tin have been investigated. Of interest were the occurrence of individual photoelectron lines as a consequence of electron correlation and relativistic effects, and the angular distribution of dominant lines in these spectra. The analysis of the experimental data shows that the 6s photoelectron spectrum of Pb is governed in the jj coupling model by initial-state configuration-interaction effects which explain the occurrence and the asymmetry parameter beta of individual lines. The same effects play a role in the 5d photoelectron spectrum, but here final ionic state configuration interaction is of equal importance. Based on these mechanisms of a complete interpretation of the 5d photoelectron spectrum of Pb is given. Surprisingly, the 4d photoelectron spectrum of Sn exhibits nearly identical structure. The asymmetry parameter beta for two 5d photoelectron lines is not yet understood; it requires a calculation which takes into account the strong correlation and relativistic effects. The asymmetry parameter beta for the 6p1/2 photoelectron line does not agree with the theoretical prediction of the relativistic Dirac-Slater calculation of Manson and co-workers (1982).