For all molecular dynamics (MD) simulations, we employed a pairwise additive model potential energy function including the standard Lennard-Jones (LJ) model representing close-range van der Waals (vw) interactions, and nonpolarizable electrostatics (el) through fixed atom-centered point charges. The total potential energy between all pairs of molecules (or molecule fragments), a 1 and a 2 , both belonging to species, A, can be written as: