Simulating monovalent and divalent ions in aqueous solution using a drude polarizable force field

An accurate representation of ion solvation in aqueous solution is critical for meaningful computer simulations of a broad range of physical and biological processes. Polarizable models based on classical Drude oscillators are introduced and parametrized for a large set of monatomic ions including cations of the alkali metals (Li⁺, Na⁺, K⁺, Rb ⁺, and Cs⁺) and alkaline earth elements (Mg²⁺, Ca²⁺, Sr²⁺, and Ba²⁺) along with Zn ²⁺ and halide anions (F^-, Cl^-, Br^-, and I^-). The models are parametrized, in conjunction with the polarizable SWM4-NDP water model [Lamoureux et al. Chem. Phys. Lett. 2006, 418, 245], to be consistent with a wide assortment of experimentally measured aqueous bulk thermodynamic properties and the energetics of small ion-water clusters. Structural and dynamic properties of the resulting ion models in aqueous solutions at infinite dilution are presented.