Successful application of fully ab initio (AI) methods in molecular dynamics (MD) simulations of ionic liquids (ILs) is hindered by their poor scalability with molecular size. The fragment molecular orbital (FMO) approach offers an exciting solution to this problem, by making any AI-based method scale linearly with molecular size.1 In this talk FMO-based calculations of IL clusters consisting of up to eight ion pairs will be compared with the standard MP2 calculations of the whole cluster.2 The ionic liquids chosen were [NMe4][BF4] and a series of imidazolium-based ILs: [C1mim][BF4], [C3mim][BF4] and [C4mim][BF4]. This systematic study focused on analysing the role of many-body effects and dispersion interactions with increasing number of ion pairs in the ionic cluster.  We showed that the FMO approach in combination with the MP2 method provided a reliable and accurate description of the interaction energies of ionic clusters, as long as three-body corrections are included. References    1. (a) Fedorov, D. G.; Kitaura, K., J. Chem. Phys. 2004, 120  , 6832; (b) Fedorov, D. G.; Kitaura, K., J. Chem. Phys. 2004, 121  , 2483.2. Izgorodina, E. I.; Rigby, J.; .MacFarlane, D. R., Chem. Commun., part of the special issue �Emerging Investigators 2012�, DOI:10.1039/C1CC15056A.

Large-scale ab initio calculations of archetypical ionic liquids using  the fragment molecular orbital approach

243rd National Meeting (2012)

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