On Photoionization in the Hard X-Ray Region

TL;DR

This paper discusses the limitations of current theoretical models in explaining photoionization experiments in the hard X-ray region, highlighting significant deviations and the need for more comprehensive theories and experiments.

Contribution

It identifies the failure of Hartree-Fock and RPA with exchange in explaining recent ionization experiments, suggesting the necessity for new theoretical and experimental approaches.

Findings

Significant deviation between theory and experiment for Ni samples.

Current models cannot account for observed ionization differences.

Highlights need for advanced theories and further experiments.

Abstract

It is demonstrated that recent experiments on ionization of 3p and 3s electrons in Ni film and solid body cannot be described in the frames of Hartree-Fock or the random phase approximation with exchange. The deviation is so big that from the theoretical side it requires inclusion of huge and yet not entirely understood effects. Perhaps, it requires also experimental efforts in order to clarify the prominent difference obtained for films and crystal samples.