Hamburg 2009 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
MO: Fachverband Molekülphysik
MO 15: Theorie: Quantenchemie
MO 15.4: Talk
Wednesday, March 4, 2009, 17:30–17:45, VMP 6 HS-F
Theoretical investigation of the proton transfer coordinates of 3-hydroxyflavone in the S0 and S1 states — •Andreas Funk1, Mihajlo Etinski2, Kristina Bartl1, Timo Fleig2, and Markus Gerhards1 — 1Physikalische und Theoretische Chemie, TU Kaiserslautern, Erwin Schrödinger-Str. 52, 67663 Kaiserslautern — 2Institut für Theoretische Chemie, Heinrich-Heine-Universität, Universitätsstr. 1, 40225 Düsseldorf
Proton transfer (PT) reactions in flavonoids play an important role for photoprotection. IR/UV experiments on 3-hydroxyflavone and its cluster with two water molecules yield, in combination with theoretical calculations, direct structural information for the electronic ground and excited state. Different partly unexpected geometries are discussed. According to the experiments a non proton transfer structure is observed for both the S0 and the S1 states but in the S1 state the proton transfer can be induced leading to an additional proton transfer structure. As PT reaction coordinates can be strongly anharmonic, an accurate theoretical description of anharmonicities is of great importance to compare the results with experiments. A strategy to analyze the frequency of the OH stretching mode involved in the PT coordinates of the S0 and S1 states is presented. The potential energy surfaces of the PT coordinates have been calculated at the DFT, time-dependent DFT and CC2 level of theory. The results are compared to the IR/UV experiments of our group.