Development of the drude polarizable force field for H₂S and QM/MM study of aqueous Mg²⁺ and Zn²⁺

Abstract

In this work, the effect of induced polarization in molecular dynamics simulations of liquids and solutions is explored. We developed a Drude polarizable model for liquid hydrogen sulfide (H₂S). The calculated thermodynamic properties for this model are in good agreement with experiment over the temperature range 212–298 K. This model is also accurate for aqueous solutions of H₂S, including the hydration free energy and diffusion coefficient. The interfacial properties of water under H₂S(g), including free energy profile and surface tension, indicate that H₂S is a powerful surfactant. To explore more sophisticated computational models, the performance of Drude model in the prediction of hydration properties of Mg²⁺ and Zn²⁺ ions was also studied. Our results show that the Drude model qualitatively describes the solvation free energy of these two ions, but QM/MM simulations are able to achieve quantitative accuracy.