The General AMBER Force Field (GAFF) Can Accurately Predict Thermodynamic and Transport Properties of Many Ionic Liquids

Abstract

We have applied molecular dynamics to calculate thermodynamic and transport properties of a set of 19 room-temperature ionic liquids. Since accurately simulating the thermophysical properties of solvents strongly depends upon the force field of choice, we tested the accuracy of the general AMBER force field, without refinement, for the case of ionic liquids. Electrostatic point charges were developed using ab initio calculations and a charge scaling factor of 0.8 to more accurately predict dynamic properties. The density, heat capacity, molar enthalpy of vaporization, self-diffusivity, and shear viscosity of the ionic liquids were computed and compared to experimentally available data, and good agreement across a wide range of cation and anion types was observed. Results show that, for a wide range of ionic liquids, the general AMBER force field, with no tuning of parameters, can reproduce a variety of thermodynamic and transport properties with similar accuracy to that of other published, often IL-specific, force fields.

Scale-Dependent Miscibility of Polylactide and Polyhydroxybutyrate: Molecular Dynamics Simulations

“…[48][49][50][51][52] Lorentz-Berthelot mixing rules were used to describe van der Waals interactions as required by the GAFF force field. 53 The topologies of the PLA and PHB monomer units were generated with the aid of the ACPYPE tool which is a wrapper for the antechamber module of Ambertools.…”

A Computational Chemical Insight into Microscopic Additive Effect on Solid Electrolyte Interphase Film Formation in Sodium-Ion Batteries: Suppression of Unstable Film Growth by Intact Fluoroethylene Carbonate

“…The GAFF force field can reasonably reproduce the thermodynamic and transport properties in ionic liquids without modifications. 37 The force field of the PF 6 -anion was obtained with reference to the previous theoretical study. 38 The atomic point charges are 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 9 obtained with the RESP method at the B3LYP/6-31+G(d) level of theory.…”

Using Molecular Simulation to Study Biocatalysis in Ionic Liquids

“…OPLS-based force fields have also been common: Latif et al (2014) and Klahn, Lim, Seduraman, et al (2011) and Klahn, Lim, and Wu (2011) used the IL family-transferable force fields developed by Canongia Pádua (2004, 2006) and Canongia Lopes, Pádua, and Shimizu (2008) to model the ILs in their studies, and Kim et al (2014) used the force field parameters developed for 68 different ILs by Sambasivarao and Acevedo (2009). Our own group, seeking to leverage the high-quality AMBER family force fields for proteins and carbohydrates, adopts the second approach and makes use of the fact that the general AMBER force field (GAFF) can reproduce many properties of neat ILs (Sprenger, Jaeger, & Pfaendtner, 2015). This has permitted seamless combining of GAFF-parameterized ILs with modern AMBER protein force fields like AMBER ff99SB (Hornak et al, 2006) and GLYCAM (Kirschner et al, 2008), the AMBER carbohydrate force field, to study many different biomolecule/IL systems Burney & Pfaendtner, 2013;Jaeger et al, 2015;Jaeger & Pfaendtner, 2013;Jarin & Pfaendtner, 2014).…”