Abstract: The mixtures of [bmim][BF₄]+water are studied by molecular dynamics simulation. The radial distribution function (RDF), local composition, as well as Kirkwood-Buff integration between different components are obtained. The simulation results show that the RDFs change regularly with the concentrations. The interaction manner between the different components can be understood more clearly through the association factor. In addition, the partial molar properties and the derivatives of activity coefficients were estimated by Kirkwood-Buff theory, which can provide valuable information of the mixture.

Key words: Ionic liquids, Molecular dynamics simulation, Radial distribution function, Local composition, Kirkwood-Buff theory