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In this work the influence of many-electron effects on the shape of characteristic X-ray emission bands of the simple metals Mg and Al are examined by means of ab initio calculations and semi-empirical models. These approaches are also used for the analysis of C K-emission and absorption spectra of graphene. Both, the dynamical screening of the core vacancy and the Auger-effect in the valence band (VB) have been taken into account. Dynamical screening of the core vacancy by valence electrons (the so-called MND effect) is considered ab initio in the framework of density functional theory. The Auger effect in VB was taken into account within a semi-empirical method, approximating the quadratic dependence of the VB hole level width on the difference between the level energy and the Fermi energy. All theoretical spectra are in very good agreement with available experimental data.
Inelastic losses are crucial to a quantitative analysis of x-ray absorption spectra. However, current treatments are semi-phenomenological in nature. Here a first-principles, many-pole generalization of the plasmon-pole model is developed for improve
With the examples of the C $K$-edge in graphite and the B $K$-edge in hexagonal BN, we demonstrate the impact of vibrational coupling and lattice distortions on the X-ray absorption near-edge structure (XANES) in 2D layered materials. Theoretical XAN
Here we report the optical and x-ray absorption (XAS) spectra of the wide-band-gap oxide MgO using density functional theory (DFT) and many-body perturbation theory (MBPT). Our comprehensive study of the electronic structure shows that while the band
We present an all-electron study of the dynamical density-response function of hexagonal close-packed transition metals Sc and Ti. We elucidate various aspects of the interplay between the crystal structure and the electron dynamics by investigating
We have studied the O 2p valence-band structure of Nb-doped SrTiO3, in which a dilute concentration of electrons are doped into the d0 band insulator, by angle-resolved photoemission spectroscopy (ARPES) measurements. We found that ARPES spectra at t