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MO: Molekülphysik

MO 10: Femtosekundenspektroskopie: Schwingungsdynamik

MO 10.2: Vortrag

Montag, 22. März 2004, 16:45–17:00, HS 315

Solvent Effects on theVibrational Relaxation of para-Nitroaniline — •Wolfgang Schreier, Tobias Schrader, Arne Sieg, Florian Koller, Wolfgang Zinth, and Peter Gilch — Sektion Physik, Ludwig-Maximilians-Universität, Oettingenstr. 67, D-80538 München, Germany

The re-distribution of excess energy released in photo-chemical processes in solution is crucial for the stabilization of the reaction products. Since these processes occur on the picosecond time scale their examination calls for advanced time resolved techniques and suitable model systems. Para-Nitroaniline (pNA) can serve as such a system. After photo-excitation pNA rapidly reforms its ground state and thereby releases 25000 cm⁻¹ of excess energy. Its transfer to the solvent surroundings has been studied in dependence of the solvent nature by optical pump-probe spectroscopy [1]. This yields a global measure for dynamics of the vibrational excitation. Here, time-resolved IR experiments on pNA yielding mode specific informations are presented. The temporal evolution of an IR line shape is evaluated and discussed in relation to solvent properties. [1] S.A. Kovalenko et al. J. Chem. Phys. 115 (2001) 3256