Hannover 2010 – scientific programme
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MO: Fachverband Molekülphysik
MO 21: Femtosecond Spectroscopy III
MO 21.5: Talk
Thursday, March 11, 2010, 15:00–15:15, F 102
Time-resolved vibrational spectroscopy of externally cold, single molecular ions — •G. Leschhorn1, S. Kahra1, T. Dou1, A. Schiffrin2, R. Ernstorfer2, R. Kienberger2, M. Kowalewski3, R. de Vivie-Riedle3, and T. Schaetz1 — 1Max-Planck-Institut für Quantenoptik (MPQ), Garching, TIaMo — 2MPQ, Garching, attosecond-beamlines — 3LMU, München
We report the preparation of externally cold and spacially well (1 µ m) localized molecular ions. A selectable amount can be provided by using techniques like RF-trapping and sympathetic cooling. These ions can serve as targets for time resolved diffraction experiments. As a first step towards this goal we are performing vibrational spectroscopy on a single magnesium hydride ion (MgH+), using a one colour pump-probe scheme in the UV (1-5 GW/cm2, pulse duration below 4 fs). For this purpose, two time delayed replica of the third gas-harmonic of a few cycle NIR pulse are used. The pump pulse launches a coherent oszillating wave packet in the first exited bound state and the probe pulse maps the intramolecular distance at a given time delay on a dissociative channel. The given UV spectrum favors or suppresses the dissociation probability for a fixed intramolecular distance. The oszillation period of the wave packet (30.9 fs) can thus be measured by observing the variation of the loss rate (dissociation) of molecular ions out of the trap. The dissociation signal of MgH+ has been observed and first measurements will be discussed. This project is part of the excellence initiative of the DFG (MAP) and financial support of MPG and IMPRS-APS is acknowledged.