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MO: Fachverband Molekülphysik
MO 35: Spectroscopy in He Droplets
MO 35.1: Talk
Friday, March 18, 2011, 10:30–10:45, MER 02
Femtosecond time-resolved EUV photoion imaging studies of pure helium nanodroplets — •Oliver Bünermann1,3, Oleg Kornilov2,3, Oliver Gessner3, Daniel M. Neumark3,4, and Stephen R. Leone3,4 — 1Institute for Physical Chemistry, Georg-August-University Göttingen — 2Max-Born-Institute, Berlin — 3Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory — 4Department of Chemistry, University of California, Berkeley
The relaxation dynamics of electronically excited helium nanodroplets are investigated by femtosecond time resolved photoion imaging studies. The droplets are excited into a broad absorption band centered at 23.8 eV. The electronic and nuclear dynamics following this excitation are monitored by photoionization with a 785nm probe pulse. A Wiley-McLaren time of flight spectrometer equipped with a time- and position sensitive delay line detector facilitates the measurement of mass selective ion kinetic energy distributions. Different relaxation processes are identified and characterized, for example the ejection of highly excited helium atoms and dimers happening on a 220 fs timescale. The combination of these results with photoelectron imaging measurements allows for a new level of insight into the electronic and nuclear dynamics of electronically excited helium nanodroplets.