Concentration Dependence of the Dielectric Permittivity, Structure and Dynamics of Aqueous NaCl Solutions: Comparison between the Drude Oscillator and Electronic Continuum Models.

International audience: We report molecular dynamics simulations of aqueous sodium chloride solutions in order to investigate the salt concentration dependence of the dielectric permittivity, the structure and the dynamics of these solutions. Different models have been applied over a large range of salt concentrations: the DRUDE oscillator model with a negative DRUDE particle, the TIP4P/2005-Reif nonpolarizable model and an electronic continuum polarizable model. Both SWM4-NDP and MDEC polarizable models were able to quantitatively reproduce the concentration dependence of the dielectric permittivity of NaCl aqueous solutions. On the contrary the non polarizable TIP4P/2005 water model fails to quantitatively predict this dependence. From a dynamics viewpoint, the MDEC model was unable to capture correctly a realistic rotational and translational dynamics while the SWM4-NDP model provided a fair agreement with the experimental translational dynamic of ions. The MDEC provided the spurious results regarding the dynamics, the structure of water and the hydration of ions even if a fair agreement with experiment was found about the concentration dependence of the dielectric permittivity of NaCl solution. The SWM4-NDP oscillator has been found as a relevant polarizable model to quantitatively reproduce the dielectric permittivity of water as function of the NaCl concentration