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MO: Molekülphysik

MO 43: Biomolecules I

MO 43.1: Talk

Wednesday, March 15, 2006, 14:00–14:15, H10

Rotationally resolved electronic spectroscopy of biomolecular building blocks — •Michael Schmitt, Marcel Böhm, Christian Ratzer und Chau Vu — Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 26.43.02, 40225 Düsseldorf

The large variety of possible conformers even of small biomolecular building blocks can easily be mapped to the experimentally determined spectra via their moments of inertia. On the other hand, rotationally resolved electronic spectra of large molecules are very congested due to their large moments of inertia. Classical techniques of line position assigned fits cannot be applied since a multitude of lines is overlapping within their line widths. In these cases, were classical techniques break down, the automated fitting based on genetic algorithms (GA) is very advantageous. Beyond the possibility of structure determinations in different electronic states, the line intensities and line shapes in the spectra can be used to obtain information about the excited state life time and about the electronic nature of the excited state via the transition dipole moment orientation. The applicability of the method will be shown exemplarily for the tryptamine system and the N-acetyltrytophaneetylester (NATE). In the case of tryptamine the energetic ordering of the excited states is examined for various conformers. NATE is an example of a protected amino acids, that opens the way to the high resolution spectroscopy of small petides. The stationary points on the conformational landscape of NATE will be explored using the combination of rotationally resolved LIF spectroscopy and the GA based fitting strategy.