J.Phys.Chem. v.100, p.16410 (1996)
Concentration Effects in Aqueous NaCl Solutions.
A Molecular Dynamics Simulation.
Alexander P. Lyubartsev and
Aatto Laaksonen
Division of Physical Chemistry, Arrhenius Laboratory,
Stockholm University, S-109 61, Stockholm, Sweden
Abstract
A series of constant-temperature/constant-pressure molecular
dynamics simulations of aqueous NaCl solution at different salt
concentrations is carried out to investigate the structure and the
dynamical properties. The simulations were performed with the number
of molecules ranging from 256 to 2000. The simulations cover several
nanoseconds to ensure the convergence of the results and enabling a
proper determination of ion-ion radial distribution functions. The
flexible SPC water model is used as the solvent, while the ions are
treated as charged Lennard-Jones particles. Only a weak influence
of the salt concentration is found on the ion-ion pair correlation
functions. The structures of the hydrated shells around ion pairs
are studied using three-body correlation functions. The self-diffusion
and interdiffusion coefficients are found decreasing with an increase
of salt concentration. Molar conductivities are calculated at different
salt concentrations. Residence times of water molecules in the hydration
shells as well as residence times of contact and solvent-separated ion
configurations are determined.
Paper (PostScript file)
Supporting information:
Hydration shells of ions
MDynaMix files:
Water: H2O.mmol
Na+ ion: Na+_SD.mmol
Cl- ion: Cl-_SD.mmol