Hannover 2010 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 7: Poster: Femtosecond Spectroscopy
MO 7.4: Poster
Dienstag, 9. März 2010, 16:00–18:30, Lichthof
Two-Photon Processes in Femtosecond Time-Resolved Four-Wave Mixing Spectroscopy: β-Carotene — •Vinu V Namboodiri, Mahesh Namboodiri, Günter Flachenecker, and Arnulf Materny — Jacobs University Bremen, Bremen, Germany
Pump-degenerate four-wave mixing (pump-DFWM) using femtosecond pulses is used to study the dynamics of excited population (S1) and ground state vibrational relaxation of β-carotene molecules in different solvents. An initial pump (IP) pulse populates the S2 state. The DFWM pulses are tuned to be in resonance with the Sn← S1 transition. Scanning the time delay between the IP and the DFWM sequence gives rise to a transient, which could not be explained up to now [1]. Recent experiments have shown that two-photon transitions have to be taken into account. A three-level kinetic model including a two-photon process is used to fit the transients and extract time constants. The time constants obtained are in agrement with previously reported values [2,3].
References:
V. Namboodiri, A. Scaria, M. Namboodiri, A. Materny, Las. Phys. 19, 154 (2009).
J. Hauer, T. Buckup, M. Motzkus, J. Phys. Chem. A 111, 10517 (2007).
D. W. McCamant, J.E. Kim, R.A. Mathies, J. Pys. Chem. A 106, 6030 (2002).