Hannover 2013 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 21: Femtosecond Spectroscopy V

MO 21.3: Vortrag

Donnerstag, 21. März 2013, 11:30–11:45, F 102

Dephasing Dynamics of Hydrogen Bonded CH-Modes in Ionic Liquids from Ultrafast CARS Spectroscopy — •Susana Chatzipapadopoulos¹, Matthias Lütgens¹, Frank Friedriszik¹, Christian Roth², Daniela Kerlé², Ralf Ludwig², Oliver Kühn¹, and Stefan Lochbrunner¹ — ¹Institut für Physik, Universität Rostock, 18051 Rostock — ²Institut für Chemie, Universität Rostock, 18051 Rostock

Currently ionic liquids (ILs) receive increasing attention as new types of solvents. To understand their unique physico-chemical properties the intermolecular forces and especially hydrogen bonds have to be investigated. Therefore we applied multiplex ultrafast coherent anti-Stokes Raman scattering (CARS) to reveal hydrogen bonds formed by CH groups of the cations with anions and to study the dynamics of the system. Multiplex CARS combines broadband excitation with narrowband probing resulting in simultaneous high spectral and temporal resolution. Recently, we approached the question of the controversially discussed existence of hydrogen bonds in ILs by Raman, IR, and CARS spectroscopy and showed that hydrogen bonding appears in imidazolium based ILs [1].

Here, we present new studies on vibrational dephasing processes of the ring CH modes, which are involved in hydrogen bonding. From the decay of the CARS signatures and the simulation of the full CARS response the dephasing times are extracted providing information about the fluctuations of the hydrogen bond network.

[1] C. Roth et al., New J. Physics 14 (2012), 105026.