Berlin 2018 – scientific programme

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O: Fachverband Oberflächenphysik

O 51: Poster: Electronic Structure of Surfaces: Spectroscopy, Surface States

O 51.6: Poster

Tuesday, March 13, 2018, 18:15–20:30, Poster B

Numerical Calculations of Metastable Induced Electron Spectra (MIES) — •Tobias Bernd Gäbler, Wichard J. D. Beenken, and Erich Runge — Technische Universität Ilmenau, Institut für Physik, Ilmenau, Germany

We present ab initio calculations of the transition rates of the Auger de-excitation of metastable helium interacting with molecules. Following the simplifying assumptions by Kantorovich et al. [Surf. Sci. 444, 31 (2000)], we calculated the exchange matrix-elements relevant for the de-excitation by a MATLAB program based on molecular orbitals as result from standard quantum-chemical software packages like Gaussian. Thereby, density functional theory (B3LYP) and the Hartree-Fock method can be utilized. Both methods show only slight differences in the calculated transition rates. However, the Hartree-Fock method may be theoretically better justified for the applicability of the Koopman's theorem, and practically preferable due to a better correspondence of calculated ionization energies with the peak positions in measured MIES spectra. We will demonstrate calculated MIES spectra averaged over given trajectories of Helium atoms along the molecule.