Molecular modelling of ionic liquids: General guidelines on fixed-charge force fields for balanced descriptions

• The widely used GAFF parameters are evaluated and refitted in a system- component-specific manner. Large-scale calculations of solvation transfer free energies ionic liquids performed. Finite-size artifacts energy more pronounced than the mass density. Thermodynamic perspectives charge scaling presented compared with bulk-property-derived one. General guidelines for molecular modelling fixed-charge force fields summarized. It has been increasingly common to investigate dynamic thermodynamic properties green solvents at atomistic scales simulation. In this work, we present detailed evaluation regime, i.e., combination scaled RESP charges derivatives. benchmark set contains three formed by cations 1-butyl-3-methylimidazolium 1-hexyl-3-methylimidazolium anions bis(trifluoromethylsulfonyl)imide PF6. For issue, two physical including density external agents selected as criteria. fast-growth simulations performed obtain thermodynamics, results further combined hydration data form water-ionic-liquids dataset, which considers partition solutes between water liquids. is observed that density-derived factor always smaller derived from solvation/partition supports use slightly larger balanced description solute-solvent solvent-solvent interactions. bonded-terms assessment, refit transferable GAFF2 derivatives generalized force-matching molecule- suggest bond-stretching angle-bending terms often problematic, while torsional potential shows satisfactory reproduction ab initio results. Finally, combining extensive computational accumulated our series works, general