A molecular model was made of ion transfer dynamics across an interface between two immiscible polar and non-polar liquids. The results of extensive molecular dynamics trajectory calculations for the ion transfer were compared with the solution of a diffusion equation for an ion moving in an external field. The external field used in the equation was obtained from an independent free energy calculation using non-Boltzmann sampling. Near quantitative agreement was found, with discrepancies that may be attributed to solvent-shell exchange dynamics.

Dynamics of Ion Transfer across a Liquid-Liquid Interface: a Comparison between Molecular Dynamics and a Diffusion Model. Benjamin, I.: The Journal of Chemical Physics, 1992, 96[1], 577-85