Düsseldorf 2007 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 52: Femtosecond Spectroscopy IV

MO 52.5: Vortrag

Donnerstag, 22. März 2007, 15:00–15:15, 6B

Femtosecond dynamics of the reexcited species
generated from the CTTS-State in aqueous solution — •Martin K. Fischer, Hristo Iglev, and Alfred Laubereau — Physik-Department E11, Technische Universität München, 85748 Garching, Germany

The dynamics of the atom:electron-pair and the solvated electron in aqueous solution are studied using femtosecond pump-probe and pump-repump-probe techniques. After excitation of 20 mM I_(aq)⁻ with a laser pulse at 200 nm wavelength in the 2nd charge-transfer-to-solvent (CTTS)-band, the resulting electron release and relaxation dynamics are investigated using probing pulses in the range 450 to 3900 nm.

Direct evidence for the second, direct detachment channel is obtained in accordance with theoretical predictions. The quantum yield of hydrated electrons is found to increase drastically as compared to excitation at 242 nm and can be traced back to a new formation channel. We will also report on novel pump-repump-probe experiments observing for the first time the atom:electron pair state predicted by quantum simulations.