München 2004 – wissenschaftliches Programm

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MO: Molekülphysik

MO 10: Femtosekundenspektroskopie: Schwingungsdynamik

MO 10.6: Vortrag

Montag, 22. März 2004, 17:45–18:00, HS 315

Study of the conformations of two-ring molecules in the gas phase - results by time-resolved femtosecond degenerate four-wave mixing — •Victor Matylitsky, Christoph Riehn, and Bernd Brutschy — Johann Wolfgang Goethe-Universität Frankfurt am Main, Institut für Physikalische und Theoretische Chemie,Marie-Curie-Str. 11, D-60439 Frankfurt am Main, Germany.

Cyclohexylbenzene (CHB), para-cyclohexylaniline (pCHA) and nicotine (3-(N-methyl-2-pyrrolidinyl)pyridine) have been studied by time-resolved femtosecond degenerate four wave mixing spectroscopy in the gas phase. All species have a low pressure at room temperature (< 0.1 mbar) and therefore have to be heated to achieve an appropriate experimental concentration. As a gas cell we have used a heat pipe oven. This experimental technique allows to investigate gaseous samples at elevated temperatures during a long time without window contamination problems. The rotational recurrences of CHB and pCHA have been analyzed in the non-rigid symmetric prolate rotor approximation. A complete fit of the fs-DFWM spectra provides values for the rotational B0 and centrifugal distortion DJ, DJK constants. The weak rotational recurrence feature of nicotine is explained by its asymmetry. Also, the influence of the different isomers of nicotine on the fs DFWM spectrum will be discussed.