Generalized Langevin dynamics simulations of NaCl electrolyte solutions

The stochastic simulation method called generalized Langevin dynamics has been employed in the study of NaCl aqueous solutions at several ionic concentrations. Only the ion pairs have been considered explicitly in the simulations. Every ion follows a generalized Langevin equation in which the total acceleration has a stochastic term, an integral time-dependent friction term, and a deterministic part that takes into account the interaction with the other ions in the system. Different solvent-averaged potentials and memory kernels have been tested in order to obtain a realistic behavior of the systems. The screening of electrostatic forces between ions has been analyzed too. The electric field around Na+ and Cl− ions has been calculated and the screening has been analyzed in terms of the structural features of the ionic surroundings.