Quantum theory of post-collision interaction in inner-shell photoionization

Abstract

We have performed fully quantum-mechanical and relativistic calculations of the post-collision-interaction effect in x-ray-induced argonK−L 2 L 3(1 D) Auger and xenonL 2−L 3 N 4(J=3) Coster-Kronig-electron emission. The Dirac-Fock computations include a complete integration over intermediate one-hole continuum states in the lowest-order expression of the resonant double-photoionization cross section. The results are in excellent agreement with synchrotron-radiation measurements of the post-collision-interaction shifts. We have also made nonrelativistic Hartree-Fock test calculations of the argonK−L 2 L 3(1 D) and xenonL 3−M 4 M 5(1 G 4) Auger-electron line shapes. The quantum-mechanical results are compared with rigorous semiclassical calculations which have been made without using the stationary-phase approximation. The results of this computational analysis are interpreted in terms of an analytical line-shape formula based on asymptotic Coulomb wave functions. As a consequence the most salient features of the post-collision interaction in inner-shell photoionization are explained.