Berlin 2005 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 26: Biological systems II

CPP 26.3: Vortrag

Dienstag, 8. März 2005, 15:45–16:00, TU C230

Structural evolution of PYP and model compounds investigated by ultrafast polarization-resolved IR spectroscopy — •Karsten Heyne, Anwar Usman, Omar F. Mohammed, Jens Dreyer und Erik T.J. Nibbering — Max-Born-Institut, Max-Born Strasse 2A, D-12489 Berlin, Germany

Vibrational spectroscopy is capable of deducing structural properties of molecules. In particular, the fingerprint region is very sensitive to structural changes. Ultrafast nonlinear vibrational spectroscopy provides access to monitor the evolution of molecular structures resulting from conformational alterations or (photo-)chemical reactions such as isomerization, dissociation, proton transfer or hydrogen bond breaking. Here, we apply polarization-resolved femtosecond UV pump IR probe spectroscopy to determine the performance of p-coumaric acid (PCT) derivatives as model compounds emulating photoisomerization dynamics of photoactive yellow protein (PYP). From parallel and perpendicular polarized IR transients we derive the relative orientation between the UV excitation and the probed IR transition dipole moments. Complementary quantum chemical studies are performed to model the results. Combining experiment and theoretical calculations provides new insight into the structural evolution of PYP after photoexcitation.