Dresden 2011 – scientific programme
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MO: Fachverband Molekülphysik
MO 24: Poster: Femtosecond spectroscopy
MO 24.15: Poster
Thursday, March 17, 2011, 16:00–18:00, P2
Investigating ultrafast molecular dynamics with a femtosecond high-harmonic VUV source — •Torsten Leitner1, Mateusz Ibek1, Michael Meyer2, and Philippe Wernet1 — 1Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin — 2European XFEL, Hamburg
The high-harmonic generation (HHG) setup at HZB provides high peak power femtosecond pulses for ultrafast IR/UV pump and VUV probe spectroscopy for experiments on molecular dynamics.
Two-color multiphoton ionization of atoms and small molecules was investigated by temporally overlapping the VUV pump and IR probe pulses. In the photoelectron spectrum, additional sidebands on both sides of the main line show up in the presence of an intense IR field. The intensity of the sidebands undergoes strong variations as a function of the relative polarization of the two fields. The amplitude of these variations differed for the 4 systems which were investigated (Ar, N2, O2, H2O). This polarization and species dependence provides direct insight into the symmetry of the outgoing electron wave and thus into the symmetry of the outer shell orbitals of the bound system.
Dissociation dynamics of molecules in gas phase is another phenomenon to be investigated with our setup under variation of the relative pump-probe delay. We constructed a high-temperature oven for evaporating solid substances, like for example NaI. First results on the dynamics of dissociating NaI are presented.