Inner shell post-collision interaction

Sch82] Schmidt V 1982 Post-collision interaction in inner-shell ionization, in X-ray and atomic inner-shell physics, ed. B Crasemann, AIP Confer. Proceed. No. 94 (AIP, New York) p. 544. [Sch86] Schmidt V 1986 Z. Physik D - Atoms, Molecules and Clusters 2 275. 

After the ejection of an electron from an inner shell, relaxation generally occurs by the emission of a secondary electron. This is known as the Auger effect. It can be reasonably well described as a two-step process, leading to double ionisation, because the primary and Auger electron are usually separate. However, if the initial photoelectron is emitted with a very low kinetic energy, then the Auger electron can catch up and interact with it. This process is described as post-collision interaction or PCI. 

Figure 19. Photoionization map for GeCl4. The inner shell hole states corresponding to atomic 2D5/2 produces the curved but roughly vertical concentrations of intensity for electron energies below 1 eV. A similar line for the 2D3/2 hole is present but hardly visible in the figure. Curvature of the lines is caused by post-collision interaction (PCI).

POST-COLLISION INTERACTION IN INNER-SHELL IONIZATION... 

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