Hamburg 2009 – scientific programme
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MO: Fachverband Molekülphysik
MO 2: Biomoleküle 1
MO 2.1: Talk
Monday, March 2, 2009, 14:00–14:15, VMP 6 HS-F
IR/UV double resonance spectroscopy on reactive isolated molecules in the S1 and T1 states — •Kristina Bartl, Andreas Funk, and Markus Gerhards — Physikalische und Theoretische Chemie, TU Kaiserslautern, Erwin Schrödinger-Str. 52, 67663 Kaiserslautern
Photochemical reactions are of great interest due to their importance in chemical and biological processes. IR/UV double and triple resonance spectroscopy in molecular beam experiments in combination with ab initio and DFT calculations yields information on reaction coordinates and Intersystem Crossing (ISC) processes subsequent to photoexcitation. We present the first applications of combined IR/UV spectroscopy on reactive isolated molecules and triplet states in molecular beams without using any messenger molecules. In the case of 3-hydroxyflavone the IR spectrum subsequent to an excited state proton transfer has been recorded. However, photoinduced reactions involve not only singlet but also triplet states. As an archetype molecule xanthone is analysed. After excitation to the S2 state, ISC occurs into the triplet manifold leading to a population of the T1 state. The IR spectrum of the T1 state has been recorded for the first time using the UV/IR/UV technique. The experimentally obtained vibrational transitions fit ideally to the calculated frequencies (DFT, B3LYP functional, TZVP basis) of the T1 state.