Development of Imidazolium-Based Parameters for AMOEBA-IL

A new approach for the efficient parametrization of thepolarizableionic liquid potential AMOEBA-IL and its application to develop parametersfor imidazolium-based cations is presented. The new approach relieson the development of parameters for fragments that can be transferredto generate new molecules. The parametrization uses the original AMOEBA-ILparametrization approach, including the use of Gaussian electrostaticmodel-distributed multipoles (GEM-DM) for the permanent multipolesand approximation of the van der Waals parameters using quantum mechanicsenergy decomposition analysis (QM-EDA) data. Based on this, functionalgroups of the selected initial structures are employed as buildingblocks to develop parameters for new imidazolium-based cations (symmetricor asymmetric) with longer alkyl chains. The parameters obtained withthis proposed method were compared with intermolecular interactionsfrom QM references via energy decomposition analysis using symmetryadapted perturbation theory (SAPT) and counterpoise-corrected totalintermolecular interactions. The validation of the new parametrizedcations was carried out by running molecular dynamics simulationson a series of imidazolium-based ionic liquids with different anionsto compare selected thermodynamic and transport properties, includingdensity rho, enthalpy of vaporization Delta H (vap), radial distribution function g(r), and diffusion coefficients D (+/-), with experimental data. Overall, the calculated gas-phase and bulkproperties show good agreement with the reference data. The new procedureprovides a straightforward approach to generating the required AMOEBA-ILparameters for any imidazolium-based cation.

Automated summary

A new efficient parametrization approach for the polarizable ionic liquid potential AMOEBA-IL is proposed and applied to develop parameters for imidazolium-based cations. The approach involves the development of parameters for fragments that can be transferred to generate new molecules. The parameters are obtained using the AMOEBA-IL parametrization approach, including the use of Gaussian electrostatic model-distributed multipoles for the permanent multipoles and approximation of the van der Waals parameters using quantum mechanics energy decomposition analysis data. Molecular dynamics simulations were conducted to validate the new parametrized cations by comparing selected thermodynamic and transport properties with experimental data.