Sum rules and spectral patterns of dichroism in inner-shell photoelectron spectra

Abstract

A theoretical description of dichroism in the photoelectron spectra of atoms polarized in different directions is presented. It is based on the general expression for the photoelectron angular distribution written in $\mathrm{LSJ}$ approximation. We show that, for photon energies far above threshold, the spectral distribution of dichroism in the photoelectron spectrum in most cases does not depend on the photoionization dynamics; for atoms with S symmetry, simple spectral patterns are obtained. Useful sum rules are given for the dichroism integrated over groups of photoelectron multiplet lines. Recent experimental data on magnetic dichroism and linear dichroism in the nonresonant inner-shell spectra of Cr $(3p$ shell), Eu $(4f$ shell), and Fe $(3p$ shell) are analyzed. An outlook is given on the dichroism in the region of autoionization resonances.