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MO: Fachverband Molekülphysik

MO 28: Poster: Theory: Molecular Dynamics

MO 28.3: Poster

Thursday, March 17, 2011, 16:00–18:00, P1

Excited State Solvation Dynamics of a Polarity Probe — Christoph Allolio and •Daniel Sebastiani — Physics Department, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany

The fluorescent dye N-methyl-6-quinolone (MQ) can be used as a probe for the local infrared spectrum in the liquid phase.[1] Femtosecond spectroscopy has given indirect access to its excited state solvation dynamics via the time dependent Stokes shift. In its protonated form (HMQ), the molecule is also a photoacid.[2] Recent results have extended its application to biochemical environments.[3] Using ab-initio molecular dynamics we examine the solvation dynamics of MQ in its ground and excited state. We discuss the effect of MQ electronic excitation on the solvent environment, focussing on the effects on hydrogen bonding and electrostatic screening. The results are compared to spectroscopical data and benchmark calculations.

• [1] Pérez Lustres, J. L.; Kovalenko, S. A.; Mosquera, M.; Senyushkina, T.; Flasche, W.; Ernsting, N. P. Angew. Chem. Int. Ed., 44, 5635-5639 (2005)
• [2] Pérez Lustres, J. L.; Rodriguez-Prieto, F.; Mosquera, M.; Senyushkina, T.; Ernsting, N. P.; Kovalenko, S. A. J. Am. Chem. Soc., 129, 5408-5418 (2007)
• [3] Sajadi, M.; Ajaj, Y.; Ioffe, I.; Weingärtner, H.; Ernsting, N. P. Angew. Chem. Int. Ed., 49, 454-457 (2010)