Modeling alkane+perfluoroalkane interactions using all-atom potentials: Failure of the usual combining rules

The ability of the optimized potentials for liquid simulation (OPLS-AA) model of alkanes and perfluoroalkanes was tested to represent the unusual mixing behavior of alkane+perfluoroalkane systems. A model for deriving intermolecular potentials using a combination of low-level ab initio calculations on single molecules and empirical adjustment of attractive terms was suggested. The model accounted for many of the liquid-phase properties of pure perfluoroalkanes and alkanes.