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MO: Fachverband Molekülphysik

MO 34: Photochemistry

MO 34.10: Vortrag

Freitag, 18. März 2011, 12:45–13:00, TOE 317

A new technique: Quadruple-resonance-spectroscopy for isomer selection in an electronically excited state — •Martin Weiler, Kristina Bartl, Andreas Funk, and Markus Gerhards — TU Kaiserslautern, Fachbereich Chemie, Erwin-Schroedinger-Strasse 52, 67663 Kaiserslautern

Photochemical reactions are of great interest due to their importance in chemical and biological processes. For the first time we have been able to observe a proton wire reaction in an isolated system, the 3-hydroxyflavone(H₂O)₂ cluster, by applying combined IR/UV spectroscopy. The IR spectra in the electronic ground and excited state seem to indicate the existence of two isomers but due to overlapping UV spectra, an UV(excitation)/IR/UV(ionization) scheme yields no isomer selectivity in a molecular beam experiment. Here we show that the new IR/UV/IR/UV quadruple-resonance-spectroscopy (with a preselecting IR excitation) solves this problem. According to this new method two different species can unambiguously be assigned in accordance to DFT calculations. The technique offers the possibility to yield isomer selection and structural assignments in excited states of reactive systems which can also be relevant in biological environments.