Regensburg 2016 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 21: Complex Fluids and Colloids IV (joint session DY/BP/CPP)

DY 21.3: Vortrag

Dienstag, 8. März 2016, 14:30–14:45, H46

All-Atom and Coarse-Grained Molecular Dynamics Simulation of Ionic Liquids — •Tamisra Pal and Michael Vogel — Institut für Festkörperphysik, Technische Universität Darmstadt, Hochschulstrasse 6, 64289 Darmstadt

Room temperature Ionic Liquids (RTILs) have garnered much interest in the last few years as they possess tremendous potential for application in industry as reaction media. The high complexity of these liquids originating from their self-assembly or nano-scale aggregate formation motivates us to understand more on their dynamics. We have employed molecular dynamics simulation for RTILs to connect the length and time scales of simulation models with different levels of molecular resolution provided by the mapping scheme. Specifically, we have investigated a coarse grained (CG) model of 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF₆]) and its all-atom (AA) description, at various temperatures. In this way, we unravel the different dynamical modes associated with dynamic heterogeneity and structural relaxation and we quantitatively compare the characteristic time scales from the two model systems to ascertain the effects of coarse graining on the dynamical behavior. The spatial and temporal aspects of molecular dynamics have been studied via calculating non-Gaussian parameters, particle displacement distributions, overlap functions and dynamic susceptibilities. Our simulation results provide a microscopic understanding to the presence of "fast" and "slow" moving particles contributing to dynamic heterogeneity and their relevance for the structural relaxation of ionic liquids.