Berlin 2018 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 30: Focus Session: Frontiers of Electronic-Structure Theory: Correlated Electron Materials VI (joint session O/MM/DS/TT/CPP)

DS 30.1: Vortrag

Donnerstag, 15. März 2018, 10:30–10:45, HL 001

Core-level spectroscopy with the GW approximation — •Dorothea Golze and Patrick Rinke — Department of Applied Physics, Aalto University, Espoo, Finland

Inner-shell spectroscopy is an important tool to characterize molecules, liquids and adsorption processes at surfaces. We present a new, accurate method for computing X-ray photoelectron spectra based on the GW approximation that overcomes the limitations of density functional theory based approaches. Green’s function theory in the GW approximation has become the method of choice for addition and removal energies of valence electrons in solids and is now increasingly being applied to molecules. However, GW core-level spectroscopy has thus far not received any attention. In most GW implementations, the self-energy is computed in the imaginary frequency domain followed by an analytic continuation to the real frequency axis. However, our calculations show that the analytic continuation becomes highly inaccurate for frequencies far away from the Fermi level and is not suitable for the computation of core excitations. Thus, we evaluate the self-energy on the real-frequency axis using the contour deformation (CD) technique. We implemented CD in combination with a resolution-of-the-identity approximation for the screened Coulomb interaction in the FHI-aims program package. Test calculations reveal that our implementation reproduces Turbomole reference calculations [1] perfectly. Furthermore, we present benchmark studies of small and medium-sized gas-phase molecules and discuss the potential of our method for more complex systems. [1] M. J. van Setten et al. JCTC, 2013, 232