Coarse-grained molecular dynamic simulations of selected thermophysical properties for 1-Butyl-3-methylimidazolium hexafluorophosphate

Abstract

Molecular dynamics (MD) simulations have been performed to compute bulk density, interfacial density profile, surface tension, viscosity, molecular orientation and dynamic spatial–temporal correlation properties (i.e. radial distribution function, van Hove self-correlation function) of 1-butyl-3-methylimidazolium hexafluorophosphate (or [bmim][PF6]). The coarse-grained (CG) force field proposed by Barghava et al. (B.L. Barghava, R. Devane, M.L. Klein, S. Balasubramanian, Soft Matter 3 (2007) 1395–1400.) has been used in all MD simulations for describing the molecular interactions of [bmim][PF6]. The quoted CG model is given by the sum of intramolecular (namely, non-bonded and bending interactions) and intermolecular contributions (van der Waals and electrostatic forces).According to the predicted results, the CG force field considered in this work proved to be useful in describing the ionic liquid nano-scale structure, its dynamical behavior, the interfacial properties and reasonably predicted some macroscopic thermodynamic properties, showing a quantitative agreement with respect to literature data. An overprediction has been observed and discussed in the high temperature range for some physical properties.