Many-body and QED effects in electron-atom inelastic scattering in EELS

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Main Authors: Iatrakis, Ioannis, Brudanin, Valerii
Format: Preprint
Published: 2025
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author Iatrakis, Ioannis
Brudanin, Valerii
author_facet Iatrakis, Ioannis
Brudanin, Valerii
contents The elemental composition and electronic structure of materials analyzed by electron energy loss spectroscopy (EELS) are probed by the inner-shell ionization of atoms. This is a localized process that can be approximated by the scattering of an electron beam from a free atom. We calculate the inelastic differential cross section perturbatively within the framework of quantum electrodynamics (QED). The interaction between the incoming electron and the atom factorizes into a high-energy electron term and the atomic transition current. The matrix elements of the transition current are computed within the relaxed Dirac Hartree Fock method. We analyze the correlation effects arising from the relaxation of the atomic orbitals induced by the creation of a core hole. These effects are particularly relevant in quantum many-body systems and have a significant impact on the shape of the differential cross section near the ionization threshold in EELS spectra. In addition to the continuum, we calculate the discrete excitation spectrum of $\mathrm{DyScO_3}$ using crystal-field multiplet theory. The calculated spectrum shows very good agreement with experimental EELS data.
format Preprint
id arxiv_https___arxiv_org_abs_2502_12254
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Many-body and QED effects in electron-atom inelastic scattering in EELS
Iatrakis, Ioannis
Brudanin, Valerii
Atomic Physics
Materials Science
The elemental composition and electronic structure of materials analyzed by electron energy loss spectroscopy (EELS) are probed by the inner-shell ionization of atoms. This is a localized process that can be approximated by the scattering of an electron beam from a free atom. We calculate the inelastic differential cross section perturbatively within the framework of quantum electrodynamics (QED). The interaction between the incoming electron and the atom factorizes into a high-energy electron term and the atomic transition current. The matrix elements of the transition current are computed within the relaxed Dirac Hartree Fock method. We analyze the correlation effects arising from the relaxation of the atomic orbitals induced by the creation of a core hole. These effects are particularly relevant in quantum many-body systems and have a significant impact on the shape of the differential cross section near the ionization threshold in EELS spectra. In addition to the continuum, we calculate the discrete excitation spectrum of $\mathrm{DyScO_3}$ using crystal-field multiplet theory. The calculated spectrum shows very good agreement with experimental EELS data.
title Many-body and QED effects in electron-atom inelastic scattering in EELS
topic Atomic Physics
Materials Science
url https://arxiv.org/abs/2502.12254