Photoionization of Argon and Xenon Including Final-State Correlation

Effects of final-state correlation on the photoionization cross sections for the $3p$ shell in argon and the $4d$ shell in xenon are calculated by the reaction-matrix method, starting from the Herman-Skillman model Hamiltonian, for photoelectron energies $0<~\epsilon <~1.2$ a.u. and $0<~\epsilon <~2.52$ a.u., respectively. The results for argon complement Hartree-Fock and other final-state correlation calculations; the results for xenon are the first ab initio calculations of this kind. Although length and velocity forms of the transition matrix element agree in the initial local-field approximation, they are shown to diverge necessarily when only the final state is improved.