A self-consistent field method to determine partial charge assignments of ionic liquids (ILs) is examined. ILs based on imidazolium cations paired with bromide, tetrafluoroborate (BF4), or bis(trifluoromethylsulfonyl)imide (Tf2N) anions are considered. By combining ab initio quantum chemistry methods and molecular dynamics simulations in the QM/MM (quantum mechanics/molecular mechanics) context, IL charge distributions are optimized in the liquid phase. The initial input charge distribution needed for self-consistent optimization is taken from the CHARMM force field, generated by ParamChem tools, for imidazolium, while the OPLS-AA charges are used for anions. Radial distribution functions and diffusion coefficients of ILs are calculated with the new optimized charges and compared with those determined the original charges.

Self-consistent field method for charge optimization in ionic liquids

248th National Meeting (2014)

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