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MO: Molekülphysik

MO 15: Biomolecules II

MO 15.5: Talk

Friday, March 4, 2005, 18:00–18:15, HU 2097

Excited state dynamics of a PYP chromophore model system explored with ultrafast infrared spectroscopy — •Anwar Usman, Omar F. Mohammed, Karsten Heyne, Jens Dreyer, and Erik T. J. Nibbering — Max Born Institut, Max Born Strasse 2A, D-12489 Berlin, Germany

Ultrafast mid-infrared spectroscopy enables the determination of dynamically evolving structures by monitoring vibrational marker modes. We perform ultrafast polarization sensitive visible pump-infrared probe spectroscopy on deprotonated trans-S-phenyl-thio-p-hydroxycinnamate, a model compound for photoactive yellow protein. We derive structural information from the observed bleach signals by comparison of the experimental frequency positions and anisotropies with results from quantum chemical calculations. The electronically excited state decays with 8 ps or 15 ps time constants for 1:1 or 10:1 DMSO:buffer, respectively, with a quantum yield for isomerization product formation less than 5