Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 67: Electronic structure of surfaces: Spectroscopy, surface states III

O 67.10: Vortrag

Mittwoch, 14. März 2018, 17:45–18:00, MA 042

Density-Functional Theory based calculation of core-level spectroscopies: Transition and Rare Earth Metals — •Georg S. Michelitsch and Karsten Reuter — Technische Universität München

Core-level spectroscopies are among the most established methods of characterization in modern material science, providing information about chemical interactions and the environment of an atomic species in a composite material matrix. A reliable interpretation of experimental signatures often requires support by computational spectroscopy. Parametrized, effective models are in most cases sufficient to explain main features or isolated resonances based on general assumptions of ligand field theory. Overlapping resonances and strong chemical shifts due to interatomic bonding instead demand an explicit calculation of the intricate electronic structure from first principles. For extended systems, the latter generally translates to density-functional theory (DFT), relying on an approximate treatment of core-hole screening via occupational constraints. While established and highly successful for light elements, this approach is challenged by transition and rare earth metals with their partially filled d- and f- states, where relativistic effects and strong local Coulomb repulsion need to be appropriately described. We assess this situation through DFT calculations for hybrid organometallic materials incorporating transition and rare earth metals with an emphasis on the impact of the chemical environment on the X-ray signatures. We find good agreement with experiment already at the level of perturbative spin-orbit coupling.