Conditional Reversible Work Coarse-Grained Models with Explicit Electrostatics-An Application to Butylmethylimidazolium Ionic Liquids

Parametrization of nonbonded interactions is fundamental in the development of new coarse-grained (CG) models. The conditional reversible work (CRW) method is unique among the systematic coarse-graining methods since it requires only the simulation of two molecules in vacuo, making parametrizations of new models computationally inexpensive. This method has been applied successfully to apolar systems and has recently been extended for the parametrization of models with explicit electrostatics. In this work, the ECRW method is used to parametrize models for butylmethylimidazolium (BMIM) ionic liquids with three different anions. Results of subsequent CG simulations are used to illustrate the strengths and weaknesses of the resulting models. In particular, the structural and dynamical properties of the bulk, as well as the behavior at the liquid-vapor interface, are studied. It is shown that the ECRW coarse-graining method produces CG models of high quality for all selected test systems.