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SYSA: Symposium Tayloring Organic Interfaces: Molecular Structures and Applications

SYSA 5: Poster Session SYSA

SYSA 5.84: Poster

Dienstag, 26. Februar 2008, 14:30–20:00, Poster A

Time-resolved investigations on reversible single-crystal-to-single-crystal photodimerisation — •Jörg Hallmann, Jav Davaasambuu, and Simone Techert — MPI for biophysical Chemistry, Am Fassber 11, 37070 Göttingen

Compounds like cinnamic acid and their derivates are known for their ability to dimerise upon light irradiation. In the following the work will concentrate on time-resolved structural studies of α-styrylpyrylium (TFMS) salts. These systems preserve periodicity upon photodimerisation and transform thermally back to the initial phase and structure. Therefore these systems are attractive candidates for optical switcher and information storage materials using light, respectively. In the following kinetic studies are presented for crystals with an edge length in the millimeter range as well as studies on single crystal films with a thickness of a few hundred nanometers. The studies concern time-resolved diffraction studies and spectroscopy of fluorescence, absorption in the VIS and IR range, and single-photo-counting. The thin crystalline films of some hundred nanometer size were used for ultrafast time-resolved optical pump - x-ray probe experiments revealing that the photo-switchable process occurs in the (sub) picosecond time regime beyond the resolution of the apparatus used. Investigations on macroscopic crystals allowed determining the time-resolved light-induced changes of the molecular structures down to electron densities.