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Multiscale Coarse-Graining of Ionic Liquids

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journal contribution
posted on 02.03.2006, 00:00 by Yanting Wang, Sergei Izvekov, Tianying Yan, Gregory A. Voth
A recently developed multiscale coarse-graining (MS−CG) approach for obtaining coarse-grained force fields from fully atomistic molecular dynamics simulation is applied to the challenging case of the EMIM+NO3- ionic liquid. The force-matching in the MS−CG methodology is accomplished with an explicit separation of bonded and nonbonded forces. While the nonbonded forces are adopted from this force-matching approach, the bonded forces are obtained from fitting the statistical configurational data from the atomistic simulations. The many-body electronic polarizability is also successfully broken into effective pair interactions. With a virial constraint fixing the system pressure, the MS−CG models rebuild satisfactory structural and thermodynamic properties for different temperatures. The MS−CG model developed from a modest atomistic simulation is therefore suitable for simulating much larger systems, because the coarse-grained models show significant time integration efficiency. This approach is expected to be general for coarse-graining other ionic liquids, as well as many other liquid-state systems. The limitations of the present coarse-graining procedure are also discussed.

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