Intensity Inversion between Main and Satellite Lines in Atomic Photoionization

Abstract

The 1s photoionization of atomic Li was studied by photoelectron spectroscopy in the photon energy region between 85 and 140 eV for the ground state and the three lowest excited configurations Li(*) 1s(2)nl, nl=2p, 3s, 3p. The importance of electron correlations was investigated by comparing the multielectron transitions, so-called shake-up and conjugate shake-up satellites, and the direct process, so-called main lines. The relative intensity of the satellites increases with the level of initial excitation of the Li atom. The shake-up process dominates for states with an n=3 valence electron and the satellites become stronger than the main lines. This spectacular effect can be explained by the spatial overlap of the initial and final state wave functions. Surprisingly, the spatial overlap affects shake-up and conjugate shake-up lines in the same way.