Berlin 2014 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 23: Femtosecond Spectroscopy 3
MO 23.5: Vortrag
Freitag, 21. März 2014, 15:00–15:15, BEBEL HS213
Femtosecond ionization dynamics of N2 studied by wavelength-selected XUV pulses — •Martin Eckstein1, Chung-Hsin Yang1, Hans-Hermann Ritze1, Fabio Frassetto2, Luca Poletto2, Marc Vrakking1, and Oleg Kornilov1 — 1Max-Born-Institut, Berlin, Germany — 2CNR-IFN, Padova, Italy
Studies of dissociative ionization of N2 have a long history both for the purpose of atmospheric research and as tests of novel experimental methods and theoretical approaches to the problem of electron correlations. A prominent example is the inner valence photoionization of N2 in the extreme ultraviolet (XUV) region of photon energies. The molecular electronic states in this region (30-50 eV) are strongly correlated and dissociate on femtosecond time scales. Despite the long history of research, the pose significant challenges for ab initio theories deterring complete explanation of the ionization dynamics. We present a novel approach using a time-compensating XUV monochromator in combination with an HHG source. The monochromator allows us to generate wavelength-selected femtosecond XUV pulses to initiate the dynamics, which is probed by multiphoton ionization by 800 nm. The time resolved photoelectron and photoion spectra recorded for six XUV photon energies between 32 eV and 50 eV reveal changes in branching ratios of several ionization channels, both resonant and non-resonant to the photon energy. The transient signals help us to identify major dissociative channels and follow the dynamics in real time. Preliminary ab initio calculations with extended basis sets will be presented and compared with experimental results.