The accurate reproduction of intermolecular electrostatic interactions in classical potentials is crucial for the proper representation of the potential energy surface. However, approximations are needed to efficiently evaluate the potential energy functions in MD simulations. One popular approximation involves atomic partial charges. These charges are able to reproduce the electrostatic potential at long range but suffer from several drawbacks including loss of charge density anisotropy and introduction of penetration errors. Another possibility is to employ distributed molecular dipoles, which provide a better description of the charge density anisotropy. We have recently shown that distributed multipoles obtained from the Gaussian Electrostatic Model (GEM) density fitting procedure can be employed in AMOEBA [JCTC, (2012) 12, 5072]. These multipoles, termed GEM–DM provide a better description of the electrostatic interaction and consequently result in more accurate calculations of bulk thermodynamic propreties for several imidazolium–based ionic liquids. To further validate the performance of GEM-DM, we have used the previously determined multipoles to calculate the bulk properties of several new imidazolium- and pyrrolidinium-based ionic liquids. The calculated properties and comparison to experimental results, as well as the parametrization procedure for several IL pairs will be presented and discussed.

Transferability of GEM distributed multipoles in AMOEBA for ionic liquids

251st National Meeting (2016)

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