Langevin-Debye model for nonlinear electrostatic screening of solvated ions.

Ion-ion interactions are central to numerous phenomena in geology, biology, and material science, but current understanding is based on linear theories of limited physical applicability. Using the Langevin-Debye model, we investigate how nonlinear dielectric saturation alters screening of electrostatic interactions between solvated charges and show that charge screening in liquids strongly depends on the charge magnitudes but negligibly on the ion radii. Qualitatively different universal screening functions are predicted for ions with charges of the same or opposite signs.