Spin–orbit-activated interchannel coupling in the 3d photoionization of barium atoms

Abstract

We have measured the NEXAFS spectrum and the relative photoionization cross section of the 3d spin–orbit components of the barium atom in the energy range up to 50 eV above the ionization threshold. As in Xe and Cs, also in barium the two spin–orbit components show strongly different energy dependence. A strong enhancement of the 3d5/2 cross section near the 3d3/2 ionization threshold, which is attributed to interchannel coupling, is observed. The experimental results are in good agreement with the relativistic time-dependent density functional theory calculations.