Berlin 2001 – scientific programme

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AMPD: EPS AMPD

AMPD 5: Sitzung 5

AMPD 5.8: Talk

Wednesday, April 4, 2001, 15:00–15:25, H105

From High-Resolution Infrared Spectroscopy to Ultrafast Intramolecular Dynamics — •Michael Hippler and Martin Quack — Laboratorium für Physikalische Chemie, ETH Zürich, CH-8092 Zürich

The detailed analysis of gas-phase IR overtone spectra allows the extraction of rovibrational Hamiltonian and time-evolution operators containing relevant dynamic information on mechanisms and time scales of fast intramolecular processes. Unfortunately, overtone spectra are often very weak and congested by hot band transitions and due to the mixture of isotopomers, which often prevents an assignment.

We have developed IR+UV double resonance techniques combining IR spectroscopy with mass spectrometry [1,2]. This allows isotopomer and mass-selective overtone spectroscopy in supersonic jet expansions, for example of aniline and benzene isotopomers. The assignment of their jet-cooled spectra gives insight into vibrational mode specific intramolecular vibrational redistribution and tunnelling processes in the fs to ps time scale.

[1] M. Hippler, M. Quack, J. Chem. Phys. 104 (1996) 7426.

[2] B. Fehrensen, M. Hippler, M. Quack, Chem. Phys. Lett. 298 (1998) 320.