First-Principles, Physically Motivated Force Field for the Ionic Liquid [BMIM][BF4]
- 24 July 2014
- journal article
- research article
- Published by American Chemical Society (ACS) in The Journal of Physical Chemistry Letters
- Vol. 5 (15), 2670-2674
- https://doi.org/10.1021/jz5010945
Abstract
Molecular simulations play an important role in establishing structure-property relations in complex fluids such as room-temperature ionic liquids. Classical force fields are the starting point when large systems or long times are of interest. These force fields must be not only accurate but also transferable. In this work, we report a physically motivated force field for the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) based on symmetry-adapted perturbation theory. The predictions (from molecular dynamics simulations) of the liquid density, enthalpy of vaporization, diffusion coefficients, viscosity, and conductivity are in excellent agreement with experiment, with no adjustable parameters. The explicit energy decomposition inherent in the force field enables a quantitative analysis of the important physical interactions in these systems. We find that polarization is crucial and there is little evidence of charge transfer. We also argue that the often used procedure of scaling down charges in molecular simulations of ionic liquids is unphysical for [BMIM][BF4]. Because all intermolecular interactions in the force field are parametrized from first-principles, we anticipate good transferability to other ionic liquid systems and physical conditions.Keywords
Funding Information
- Basic Energy Sciences (DE-FG02-09ER16059)
- National Science Foundation (CHE-1111835)
This publication has 45 references indexed in Scilit:
- Force Fields for Studying the Structure and Dynamics of Ionic Liquids: A Critical Review of Recent DevelopmentsChemphyschem, 2012
- Energy applications of ionic liquidsEnergy & Environmental Science, 2009
- Development of OPLS-AA Force Field Parameters for 68 Unique Ionic LiquidsJournal of Chemical Theory and Computation, 2009
- Modelling room temperature ionic liquidsChemical Communications, 2008
- Ionic liquids in catalysisCoordination Chemistry Reviews, 2004
- Computational Study of Room Temperature Molten Salts Composed by 1-Alkyl-3-methylimidazolium CationsForce-Field Proposal and ValidationThe Journal of Physical Chemistry B, 2002
- Ionic Liquid (Molten Salt) Phase Organometallic CatalysisChemical Reviews, 2002
- Solubilities and Thermodynamic Properties of Gases in the Ionic Liquid 1-n-Butyl-3-methylimidazolium HexafluorophosphateThe Journal of Physical Chemistry B, 2002
- Room-Temperature Ionic Liquids. Solvents for Synthesis and CatalysisChemical Reviews, 1999
- Perturbation Theory Approach to Intermolecular Potential Energy Surfaces of van der Waals ComplexesChemical Reviews, 1994