Calculation of Ar photoelectron satellites in hard X-ray region

TL;DR

This paper calculates the intensities of Ar 1s photoelectron satellite lines in the hard X-ray region using many-body perturbation theory, revealing the roles of shake-up and knock-up processes in the spectra.

Contribution

It introduces a detailed theoretical calculation of Ar photoelectron satellites, emphasizing the importance of direct knock-up processes alongside shake-up excitations.

Findings

Support for interpreting intense lines as 2p 4p shake-up excitations.

Demonstration that 4s and 3d excited states require considering knock-up processes.

Quantitative agreement with experimental spectra.

Abstract

The intensities of photoelectron satellite lines, corresponding to double core hole (DCH) states of Ar 1s ionization by hard X-rays are calculated using the many-body-perturbation theory. Calculations support the interpretation of the most intense lines as the shake-up excitations 2p 4p. It is demonstrated that the intensities of the spectrum lines corresponding to 4s (and 3d) excited states in DCH field can be explained only taking into account the direct knock-up process 2p 3d along with shake-up process 1s 4s that accompanies 2p photoionization.