Mainz 2017 – scientific programme

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MO: Fachverband Molekülphysik

MO 17: Experimental Techniques

MO 17.2: Talk

Friday, March 10, 2017, 11:30–11:45, N 6

New pump-probe IToF setup to unravel ultra-fast photo conversion processes — •Mario Niebuhr, Dennis Mayer, Tom Neumann, Axel Heuer, and Markus Gühr — Institute for Physics and Astronomy, Uni Potsdam, Germany

Ultra-fast pump-probe spectroscopy of isolated molecules presents an important step towards understanding photo conversion processes and provides benchmark data for high-level ab-initio calculations. We are especially interested in photoisomerization systems such as azobenzene, and molecules, such as nucleobases, that are able to withstand energetic UV irradiation through very fast, non-ionizing and non-dissociating relaxation channels.

Our new setup utilizes time-of-flight mass spectroscopy to obtain delay dependent signals from excited state intramolecular conversion processes with femtosecond time resolution. We use a commercial 100 kHz Yb:KGW system and it’s harmonics for pumping as well as probing. As the pulses for Yb based lasers are typically in the several 100 fs range, noncollinear parametric amplifiers (NOPAs) and fiber based spectral broadening are employed to access the sub hundred fs regime. First data of delay-dependent ion fragmentation yields will be presented.