Dressing a Nonpolarizable\nForce Field for OH<sup>–</sup> in TIP4P/2005 Aqueous Solutions\nwith Corrected Hirshfeld Charges

We present a rigid model for the OH<sup>–</sup> ion parametrized\nfor binary mixtures with TIP4P/2005-type water molecules. Li<sup>+</sup>, Na<sup>+</sup> and K<sup>+</sup> were selected as counterions,\nhence mimicking the important and widely used solutions of soluble\nalkaline hydroxides. The optimized atomic charge distributions were\nobtained by scaling in a factor of 0.85 those derived from the atomic\ndipole corrected Hirshfeld approach. The agreement between experimental\nand Molecular Dynamics simulation results is remarkable for a set\nof properties, namely, the dependence of the density of the solutions\non the hydroxide concentration and on temperature, the structure (i.e.,\npositions of the atom-to-atom radial distribution functions and coordination\nnumbers), the viscosity coefficients, the surface tension, or the\nfreezing point depression. The proposed optimized potential parameters\nfor OH<sup>–</sup> thus enlarge the set of models comprised\nwithin the Madrid–2019 force field and widen the potential\napplicability of the TIP4P/2005 water model in basic environments.