A Kirkwood-Buff Derived Force Field for Aqueous Alkali Halides

摘要

A classical nonpolarizable force field is presented for the simulation of aqueous alkali halide solutions (MX), where M =Li~+, Na~+, K~+, Rb~+, and Cs~+ and X = F~-, Cl~-, Br~-, and I~-, and their interactions with biomolecules. The models arespecifically designed to reproduce the experimental Kirkwood-Buff integrals, and thereby the solution salt activities, as afunction of salt concentration. Additionally, we demonstrate that these models reasonably reproduce other experimentalproperties including ion diffusion constants, dielectric decrements, and the excess heats of mixing. The parameters aredeveloped by considering the properties of aqueous NaX and MCl solutions using a previously established model for NaCl.Transferability of the parameters to other salts is then established by the successful simulation of additional aqueous saltsolutions, KI and CsBr, not originally included in the parametrization procedure.