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SYFM: Symposium Quantenkontrolle funktionaler Moleküle

SYFM 1: Quantum control of functional molecules I

SYFM 1.2: Hauptvortrag

Mittwoch, 21. März 2007, 14:30–15:00, 6C

Ultrafast ring-opening and ring-closure reaction of photochromic molecular switches - indolylfulgides — •Markus Braun, Simone Draxler, Thomas Brust, Stephan Malkmus, Florian Koller, and Björn Heinz — Lehrstuhl für BioMolekulare Optik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 München

Photochromic molecules are characterized by a reversible rearrangement of their structure (isomerization) due to light illumination, connected with changes in their color (probed by e.g. absorption in the UV/VIS and mid-IR or fluorescence). Indolyl substituted fulgides and fulgimides are known for their thermally stable and photochemically robust isomers (C, E and Z), which can be addressed optically by well-separated absorption bands. The control of the structural dynamics and reaction yield of the pericyclic isomerization is investigated by steady-state and fs-time resolved pump-probe spectroscopy. These experiments show that isomerization occurs within a few picoseconds or even faster. Photochemical parameters as temperature, polarity or optical excitation conditions allow for an optimization of the reaction yields. Application of optical prepulses influences the excited state dynamics and the isomerization yield.