Hannover 2013 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 14: Poster 1: Cluster, Femtosecond Spectroscopy
MO 14.5: Poster
Dienstag, 19. März 2013, 16:00–18:30, Empore Lichthof
Fingerprints of adiabatic versus diabatic vibronic dynamics in the asymmetry of photoelectron momentum distributions — •Mirjam Falge1, Volker Engel1, and Stefanie Gräfe2 — 1Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Emil-Fischer-Str. 42, Am Hubland, 97074 Würzburg, Germany — 2Institut für Theoretische Physik Technische Universität Wien, Wiedner Hauptstrasse 8-10, A-1040 Wien, Austria
When the Born-Oppenheimer approximation is valid, electrons follow adiabatically the nuclear motion in molecules. For strong non-adiabatic coupling between electronic states, one encounters a diabatic motion where the electrons remain local and do not adapt to molecular geometry changes. We show that the mentioned limiting cases are reflected differently in the asymmetry of time-resolved photoelectron momentum distributions. Whereas for adiabatic dynamics, the asymmetry directly maps the time-dependent average nuclear momentum, in the diabatic case the asymmetry is determined by a non-classical interference effect arising from the mixing of wave function components in different electronic states which is present at times non-adiabatic transitions take place.