Dresden 2014 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 3: Ionic Liquids
CPP 3.6: Vortrag
Montag, 31. März 2014, 11:15–11:30, ZEU 260
Vibrational dynamics of the C-H stretch region of imidazolium based ionic liquids:[C2mim][NTf2] — •Tobias Zentel1, Susana Chatzipapadopoulos1, Matthias Lütgens1, Sergei D. Ivanov1, Stefan Lochbrunner1, Ralf Ludwig2, and Oliver Kühn1 — 1Institut für Physik, Universität Rostock — 2Institut für Chemie, Universität Rostock
To understand the physico-chemical properties of ionic liquids, the knowledge of intermolecular interactions is of utmost importance. The ionic character of the molecules leads to strong Coulomb forces, but also a distinct hydrogen bond network exists [1]. In this contribution we focus on the dynamics of their hydrogen bonds under the influence of the fluctuating environment. Using force field based molecular dynamics (MD) simulation and ab initio methods as well as ultrafast coherent anti Stokes Raman spectroscopy (CARS), the C-H stretch modes located on the imidazolium ring of the aprotic ionic liquid [C2mim][NTf2] are used as sensors for the hydrogen bond interactions.
Following Oxtoby et al. [2] the force projected on the C-H bonds is utilized to obtain frequency fluctuations and frequency correlation functions along the bulk MD trajectory. This allows to calculate dephasing times which in accord with CARS results show a distinct dependence on the H-bonding site. The force field results are scrutinized by DFT calculations.
[1] C. Roth et al. New J. Phys. 14,105026 (2012)
[2] D. Oxtoby, D. Levesque, J. Weis J.Chem.Phys 68,5528, 1978