Berlin 2014 – scientific programme

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MO: Fachverband Molekülphysik

MO 19: Femtosecond Spectroscopy 2

MO 19.3: Talk

Thursday, March 20, 2014, 17:00–17:15, BEBEL HS213

H-bond analysis of acetic acid by spontaneous and coherent Raman spectroscopy — •Matthias Lütgens, Frank Friedriszik, Susana Chatzipapadopoulos, and Stefan Lochbrunner — Institut für Physik, Universität Rostock, 18055 Rostock

The formation of hydrogen bonds leads in many liquids to the appearance of molecular complexes and greatly affects their macroscopic properties. The structural motives of acetic acid (AA) are still under intense investigation, since AA has multiple H-bond donor and acceptor sites allowing for several configurations. The H-bonded complexes are investigated by comparing spontaneous Raman and coherent anti-Stokes Raman scattering (CARS) spectra of the C=O vibration. The spontaneous Raman spectrum shows three distinct features but cannot clearly decide if a fourth mode is contributing or not. CARS measurements with coherent excitation of the C=O band via a femtosecond Stokes and a narrowband Raman pump pulse followed by a narrowband probe pulse in the ps range can discriminate slow dephasing modes from faster dephasing vibrational contributions.[1] They reveal an additional mode hidden under the dominating broad Raman band proofing the coexistence of more than one H-bonded configuration in liquid AA.
M. Lütgens, S. Chatzipapadopoulos, and S. Lochbrunner, Opt. Express 20, 6478-6487 (2012)