(301f) Influence of Polarization Interactions On Properties of Ionic Liquids Predicted From Molecular Dynamics Simulations

Utilizing the transferable, quantum chemistry-based, polarizable APPLE&P? force field, we have systematically investigated the influence of polarization effects on the accuracy of structural, dynamic and interfacial properties predicted from molecular dynamics simulations of various room temperature ionic liquids (ILs). Simulations of ILs in which the atom based polarizability was set to zero for all atoms (non-polarizable APPLE&P potential) resulted in changes in thermodynamic and dynamic properties from those predicted by the polarizable APPLE&P potential that are qualitatively different to changes observed for non-ionic liquids. Investigation of structural and dynamical correlations using both the polarizable and non-polarizable versions of APPLE&P allowed us to obtain a mechanistic understanding of the influence of polarization on dynamics in the ILs investigated. Additionally, the Force Matching (FM) approach was employed to systematically obtain non-polarizable two-body force fields for several ILs that reproduce as accurately as possible intermolecular forces predicted by the polarizable model. For most ILs the FM approach does not result in a two-body potential that accurately reproduces either structure or dynamics predicted by the polarizable IL model. However, for ILs with anions containing cyano groups for which non-polarizable APPLE&P model predicted qualitatively different structure than the polrizable model, the FM approach allowed to obtain a non-polarizable force field that captures all structural correlations observed in simulations using polarizable force field.