Molecular Dynamics Study of the Ionic Liquid 1-n-Butyl-3-methylimidazolium Hexafluorophosphate

Abstract

We report the results of a molecular dynamics study of the ionic liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF 6 ], a widely studied ionic liquid. An all-atom force field is developed using a combination of density functional theory calculations and CHARMM 22 parameter values. Molecular dynamics simulations are carried out in the isothermal-isobaric ensemble at three different temperatures. Quantities computed include infrared frequencies, molar volumes, volume expansivities, isothermal compressibililties, self-diffusivities, cation-anion exchange rates, rotational dynamics, and radial distribution functions. Computed thermodynamic properties are in good agreement with available experimental values.

Triazolium-Based Energetic Ionic Liquids

“…7 Two recent computer simulations of 1-butyl,3-methylimidazolium (bmim + )/PF 6 -show at least two different time scales for diffusion in such solvents, 8 and yield information on preferred structures. 9 An experimental 10 study of the interaction of water with the surface layer of this IL, known to be immiscible with water, observed structural changes consistent with the latter simulation.…”

Molecular Dynamics Study of Thermodynamic Scaling of the Glass-Transition Dynamics in Ionic Liquids over Wide Temperature and Pressure Ranges

“…30 A similar situation has been found in several ionic liquids. 18,19,23 Examples of the MSD for EMIM + ions in several conditions are shown in Figure 1a. Solid (blue) curves are for the data in ∼0.1 MPa at several temperatures.…”

“…[18][19][20][21][22][23][24] It is a sum of bond, angle, and dihedral deformation energies, the pairwise standard (6,12) Lennard-Jones potential representing the repulsive term and van der Waals interactions, and Coulombic interactions between atoms with charges q i . The parameters therein were taken from the general Amber force field.…”

Assessing the Roles of the Constituents of Ionic Liquids in Dynamic Solvation: Comparison of an Ionic Liquid in Micellar and Bulk Form

“…[1][2][3][4] The importance of ionic liquids has consequently stimulated considerable interest in their dynamic solvation properties, both in the experimental and the theoretical arenas. [26][27][28][29][30][31][32] An intriguing aspect of certain ionic liquids, which has only recently become appreciated, is their ability to promote micelle formation or to form micelles themselves. [33][34][35][36] Major questions regarding dynamic solvation by ionic liquids deal with whether the organic cation or the inorganic anion solvate preferentially on different time scales, the role of the correlated motion of the ion pairs and their lifetime, and the importance of translational motion of the ions relative to dipolar relaxation.…”