Photo-Auger ionization of lithiumlike ions

Abstract
The photo-Auger ionization process is a higher-order contribution to the direct photoelectric effect in which photoexcitation of an inner-shell electron is followed by the emission of an Auger electron. The frequency-integrated photo-Auger ionization cross section for ions of the lithium isoelectronic sequence is calculated in the isolated resonance approximation. The effects of transitions into all accessible intermediate states are explicitly included. Results are compared with the frequency-integrated direct photoionization cross section. The relative contribution of the photo-Auger effect for three-electron ions is a maximum in the Ne(7 +) region, where it is of order 70% of the direct process.