Stuttgart 2012 – scientific programme

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MO: Fachverband Molekülphysik

MO 13: Poster 1: Cold Molecules, Femtosecond Spectroscopy, Molecular Dynamics

MO 13.23: Poster

Tuesday, March 13, 2012, 16:30–19:00, Poster.IV

Investigation of vibrational coherence generation by femtosecond two-pulse excitation experiments — •Jan Philip Kraack, Marcus Motzkus, and Tiago Buckup — Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany

Vibrational coherences in nonlinear optical spectroscopy are prepared by two distinct light-matter interactions. These may take place within the temporal envelope of a single excitation pulse of femtosecond time duration in, e.g., two-pulse pump-probe spectroscopy. Alternatively, each interaction may take place within the temporal envelope of independent excitation pulses as in, e.g., three-pulse Degenerate Four-Wave-Mixing (DFWM)[1]. The application of two distinct excitation pulses in DFWM offers important advantages over single excitation pulse techniques regarding investigations of electronic coherence dynamics. We experimentally and theoretically investigated effects of variable interpulse delays between excitation pulses in spectrally-resolved and -integrated DFWM. Clear oscillatory modulation of normal mode signal intensities is observed for a series of samples with different vibrational characteristics when the interpulse delay is scanned. These modulation effects are strongly dependent on the displacements between involved electronic states as well as the number of involved vibrational modes.

[1]Kraack, J. P.; Motzkus, M.; Buckup, T. The Journal of Chemical Physics 2011, 135, 224505.