Hannover 2016 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 3: Electronic Spectroscopy 1

MO 3.1: Vortrag

Montag, 29. Februar 2016, 14:30–14:45, f102

Theoretical soft X-ray spectroscopy from time correlation functions — •Sven Karsten, Sergey Bokarev, Sergei Ivanov, and Oliver Kühn — Institut für Physik, Universität Rostock, Rostock

Soft X-ray spectroscopy can reveal element-specific information about the electronic structure of an absorbing atom and its interactions with the local environment. The interpretation of experimental X-ray spectra requires a detailed theoretical consideration of the core-excited electronic states. Conventionally, the electronic spectra are obtained via single point calculations combined with phenomenological broadening. A more realistic account of vibrational and environmental effects is commonly provided by an incoherent sampling of molecular dynamics (MD) trajectories. However, this completely neglects nuclear dynamical correlations. In the present contribution such correlations are included via a rigorous reformulation of X-ray absorption spectra (XAS) and resonant inelastic X-ray scattering spectra (RIXS) in terms of transition dipole correlation functions. The time evolution is provided by ground state (ab initio) MD simulations. Performing DFT or RASSCF static point calculations for each MD snapshot yields, upon tracing the entire manifold of relevant electronic levels, all necessary ingredients. The success of the proposed methodology is exemplified for oxygen K-edge XAS and RIXS of bulk water which provides insight into H-bond dynamics.