Solid density of different NaCl force fields (see references in Table I) at 0 pressure obtained using NPT MD simulations. The results are compared with the experimental values (Ref. 26).
Phase diagram of pure NaCl. NVT simulation results from a slab geometry, using the last line of Table I, are shown with filled circles. The NPT simulation results for the liquid and solid phases are shown with filled squares. The solid continuous line in the liquid and vapor phases are results from Guissani and Guillot (Ref. 25). The experimental (Ref. 26) results of the solid and liquid phases are shown by a discontinuous line and by open circles, respectively.
Surface tension of new NaCl force field (last line of Table I). The filled circles are results from this work, the filled squares are results for the Tosi–Fumi model (Ref. 31) and the open circles are experimental values (Ref. 31).
Liquid-vapor phase diagram of the rigid SPC/E (Ref. 35), TIP4P/2005 (Ref. 36), and flexible SPCE-FH water models. The results are compared to experimental data (Ref. 37) (full line).
Surface tension of the rigid SPC/E (Ref. 35), TIP4P/2005 (Ref. 36), and flexible SPCE-FH water models. The experimental data (Ref. 37) are shown with a continuous line. The error bars are around the same size as the symbols.
Clustering of NaCl using the TIP4P/2005 model with (dashed line) and without (continuous line) LJ interactions between water-H sites and ions at solution (420 water molecules and 40 NaCl pairs).
Pair distribution functions of NaCl in a solution, using the TIP4P/2005 model and the new NaCl force field. (a) Without H–Cl and H–Na LJ interaction. (b) With H–Cl and H–Na LJ interaction.
Pair distribution functions of ion-water pairs for ionic solutions at concentration with (continuous line) and without (discontinuous line) LJ interactions between Cl–H pairs.
Clustering of NaCl at 300 K, 1 atm, and ionic concentration of (458 water molecules and 21 NaCl pairs). Results are for rigid SPC/E (dashed line) and fully flexible SPCE-F (continuous line) water models.
Ion-water pair distribution functions using the rigid and flexible water models at 300 K, 1 atm, and ionic concentration of (480 water molecules and ten NaCl pairs). The results are almost indistinguishable for the different models.
Water-ion pair distribution functions at 300 K and 1 atm for a solution using the rigid and flexible water models. The experimental (Refs. 38–40) data (circles) and MD ab initio results (Ref. 41) (squares) are shown for the Cl–H, Na–O, and Cl–O pairs. The experimental values of Cl–H and Cl–O were obtained from 2 molal solutions (Refs. 38 and 39) of at and 1 bar; and Na–O from a solution (Ref. 40) of . The ab initio MD results are for a solution.
Results of the electric current autocorrelation function obtained with rigid and flexible force fields of water. (a) Ionic concentration of . (b) Ionic concentration of .
Electric conductivity of NaCl solutions as a function of salt concentration using the rigid and flexible water models with the new NaCl force field (last line in Table I).
Lennard-Jones parameters of NaCl force fields. The cross interactions in the WS model are calculated using the geometric mixing rules and the parameter is scaled by a factor of 0.75. In the KR model and . The units are in Å, in , in , in Å, and potential energy per ion, in .
Force field and molecular parameters of water models. The SPC/E and TIP4P/2005 are fully rigid while SPCE-FH is fully flexible. The units are distance and in Å, in , and charge in . The spring constants and have units of and , respectively.
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