@article {794, title = {Diffusion Mechanisms in Smectic Ionic Liquid Crystals: Insights from Coarse-grained MD Simulations}, journal = {Soft Matter}, volume = {9}, year = {2013}, pages = {5716-5725}, doi = {10.1039/C3SM50375E}, author = {G. Saielli and G. A. Voth and Wang, Y.} } @article {702, title = {Molecular Dynamics Simulations of Polyglutamine Aggregation using Solvent-Free Multiscale Coarse-Grained Models}, journal = {J. Phys. Chem. B}, volume = {114}, year = {2010}, pages = {8735{\textendash}8743}, doi = {10.1021/jp1007768}, author = {Wang, Y. and G. A. Voth} } @article {699, title = {Effective Force Coarse-Graining}, journal = {Phys. Chem. Chem. Phys.}, volume = {11}, year = {2009}, pages = {2002-2015}, doi = {10.1039/B819182D}, author = {Wang, Y. and Noid, W. G. and Liu, P. and G. A. Voth} } @article {696, title = {Transferable Coarse-Grained Models for Ionic Liquids}, journal = {J. Chem. Theor. Comp.}, volume = {5}, year = {2009}, pages = {1091-1098}, doi = {10.1021/ct800548t}, author = {Wang, Y. and Feng, S. and G. A. Voth} } @article {503, title = {Molecular Dynamics Simulation of the Energetic Room Temperature Ionic Liquid 1-Hydroxyethyl-4Amino-1, 2, 4-Triazolium Nitrate (HEATN)}, journal = {J. Phys. Chem. B}, volume = {112}, year = {2008}, pages = {3121-3131}, doi = {10.1021/jp710653g}, author = {Jiang, W. and T. Yan and Wang, Y. and G. A. Voth} } @article {585, title = {The Multiscale Coarse-graining Method. II. Numerical Implementation for Coarse-grained Molecular Models}, journal = {J. Chem. Phys.}, volume = {128}, year = {2008}, pages = {244115}, doi = {10.1063/1.2938857}, author = {Noid, W. G. and Liu, P. and Wang, Y. and Chu, J.-W. and Ayton, G. S. and Izvekov, S. and Andersen, H. C. and G. A. Voth} } @article {502, title = {A Multiscale Coarse-Graining Study of Liquid/Vacuum Interface of Room-Temperature Ionic Liquids with Alkyl Substituents of Different Lengths}, journal = {J. Phys. Chem. C}, volume = {112}, year = {2008}, pages = {1132-1139}, doi = {10.1021/jp077643m}, author = {Jiang, W. and Wang, Y. and T. Yan and G. A. Voth} } @article {501, title = {Molecular Dynamics Simulation of Nanostructural Organization in Ionic Liquid/Water Mixtures}, journal = {J Phys Chem B}, volume = {111}, number = {18}, year = {2007}, note = {Jiang, Wei Wang, Yanting Voth, Gregory A Research Support, U.S. Gov{\textquoteright}t, Non-P.H.S. United States The journal of physical chemistry. B J Phys Chem B. 2007 May 10;111(18):4812-8. Epub 2007 Feb 27.}, pages = {4812-8}, abstract = {

Molecular dynamics simulations have been carried out to investigate nanostructural organization in mixtures of 1-octyl-3-methylimidazolium nitrate ionic liquid and water at multiple water concentrations. Evolution of the polar network, water network, and micelle structures is visualized and analyzed via partial radial distribution functions. The calculated static partial structure factors show that within the range of water contents examined, polar networks, water networks, and micelles possess an approximately invariant characteristic length at around 20 A. Furthermore, the above calculations point out that, as the amount of water increases, the polar network is continuously broken up (screened) by the intruding water, while the structural organization of the water network and the micelle exhibits a turnover. At the turnover point, the most ordered micelle (cation-cation) structure and water (water-anion-water) network are formed. Thereafter, the structural organization abates drastically, and only loose micelle structure exists due to the dominant water-water interactions. The simulated turnover of structural organization agrees with the sharpest peak in the experimentally obtained structure factor in aqueous solutions of similar ionic liquids; the simulated water structure reveals that water can form liquidlike associated aggregates due to the planar symmetry and strong basicity of NO(3)-, in agreement with experiment. The turnover of structural organization of micelles results from the persistent competition between the hydrophobic interactions of the nonpolar groups and the breakup of the charged polar network with increasing water content, whereas the turnover of the water network results from the competition between the water-water and water-anion interactions.

}, keywords = {*Computer Simulation Imidazoles/*chemistry Ionic Liquids/*chemistry Micelles *Models, Chemical Models, Molecular Molecular Structure Nanostructures/*chemistry Water/chemistry}, doi = {10.1021/jp067142l}, author = {Jiang, W. and Wang, Y. and G. A. Voth} } @inbook {743, title = {Spatial Heterogeneity in Ionic Liquids}, booktitle = {Ionic Liquids IV. Not Just Solvents Anymore}, year = {2007}, pages = {272-307}, publisher = {American Chemical Society}, organization = {American Chemical Society}, address = {Washington DC}, doi = {10.1021/bk-2007-0975.ch020}, author = {Wang, Y. and Jiang, W. and G. A. Voth}, editor = {Brennecke, J. F. and Rogers, R. D. and Seddon, K. R.} } @article {698, title = {Understanding ionic liquids through atomistic and coarse-grained molecular dynamics simulations}, journal = {Acc Chem Res}, volume = {40}, number = {11}, year = {2007}, note = {Wang, Yanting Jiang, Wei Yan, Tianying Voth, Gregory A Research Support, Non-U.S. Gov{\textquoteright}t Research Support, U.S. Gov{\textquoteright}t, Non-P.H.S. Review United States Accounts of chemical research Acc Chem Res. 2007 Nov;40(11):1193-9. Epub 2007 Oct 13.}, pages = {1193-9}, abstract = {

Understanding the physical properties of ionic liquids (ILs) via computer simulation is important for their potential technological applications. The goal of our IL research is to obtain a unified understanding of the properties of ILs with respect to their underlying molecular structure. From atomistic molecular dynamics simulations, the many-body electronic polarization effect was found to be important for modeling ILs, especially their dynamics. The multiscale coarse-graining methodology has also been employed to increase the simulation speed by a factor of 100 or more, thereby making it possible to study the mesoscopic behavior of ILs by computer simulations. With these simulation techniques, ILs with an amphiphilic cation were found to exhibit a spatial heterogeneity due to the aggregation of their nonpolar alkyl tails. This spatial heterogeneity is a key feature in interpreting many physical phenomena of ILs, such as their heterogeneous self-diffusion and surface layering, as well as their surfactant-like micelles formed in IL/water mixtures.

}, keywords = {Chemical Models, Chemistry, Molecular Physicochemical Phenomena Surface Properties, Physical *Computer Simulation Ionic Liquids/*chemistry *Models}, doi = {10.1021/ar700160p}, author = {Wang, Y. and Jiang, W. and T. Yan and G. A. Voth} } @article {697, title = {Multiscale Coarse-Graining of Ionic Liquids}, journal = {J Phys Chem B}, volume = {110}, number = {8}, year = {2006}, note = {Wang, Yanting Izvekov, Sergei Yan, Tianying Voth, Gregory A Research Support, U.S. Gov{\textquoteright}t, Non-P.H.S. United States The journal of physical chemistry. B J Phys Chem B. 2006 Mar 2;110(8):3564-75.}, pages = {3564-75}, abstract = {

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.

}, keywords = {*Algorithms Ionic Liquids/*chemistry Temperature}, doi = {10.1021/jp0548220}, author = {Wang, Y. and Izvekov, S. and T. Yan and G. A. Voth} } @article {701, title = {Tail Aggregation and Domain Diffusion in Ionic Liquids}, journal = {J Phys Chem B}, volume = {110}, number = {37}, year = {2006}, note = {Wang, Yanting Voth, Gregory A Research Support, U.S. Gov{\textquoteright}t, Non-P.H.S. United States The journal of physical chemistry. B J Phys Chem B. 2006 Sep 21;110(37):18601-8.}, pages = {18601-8}, abstract = {

An extended multiscale coarse-graining model for ionic liquids is used to investigate the liquid crystal-like phase in certain ionic liquids. The tail groups of the cations with a sufficient side-chain length are found to aggregate, forming spatially heterogeneous domains, due to the competition between the electrostatic interactions between the charged head groups and the anions and the collective short-range interactions between the neutral tail groups. With a sufficiently long alkyl chain at a low enough temperature, the tail domains remain relatively stable, despite the diffusion of individual ions in the liquid phase. With increasing temperature, the average tail domains begin to diffuse, while beyond a transition temperature, their average density has an almost uniform distribution, although the tail groups still form instantaneous domains.

}, keywords = {Carbon/chemistry Cations Chemistry, Molecular Models, Physical/*methods Diffusion Gas Chromatography-Mass Spectrometry/methods *Ions Liquid Crystals Models, Statistical Software Solvents Static Electricity Temperature}, doi = {10.1021/jp063199w}, author = {Wang, Y. and G. A. Voth} } @article {700, title = {Unique Spatial Heterogeneity in Ionic Liquids}, journal = {J Am Chem Soc}, volume = {127}, number = {35}, year = {2005}, note = {Wang, Yanting Voth, Gregory A United States Journal of the American Chemical Society J Am Chem Soc. 2005 Sep 7;127(35):12192-3.}, pages = {12192-3}, abstract = {

A multiscale coarse-graining model for ionic liquids has been extended to investigate the unique aggregation of cations in ionic liquids through computer simulation. It has been found that, with sufficiently long side chains, the tail groups of cations aggregate to form spatially heterogeneous domains, while headgroups of the cations and the anions distribute as uniformly as possible. This is understood as the result of competition between the charged electrostatic interactions between headgroups and anions and the collective short-range interactions between the neutral tail groups. This aggregation can help to explain a number of experimentally observed physical phenomena in ionic liquids.

}, doi = {10.1021/ja053796g}, author = {Wang, Y. and G. A. Voth} }