In this paper we investigate the possibility to detect the hypothesized
liquid-liquid critical point of water in supercooled aqueous solutions of
salts. Molecular dynamics computer simulations are conducted on bulk TIP4P
water and on an aqueous solution of sodium chloride in TIP4P water, with
concentration c = 0.67 mol/kg. The liquid-liquid critical point is found both
in the bulk and in the solution. Its position in the thermodynamic plane shifts
to higher temperature and lower pressure for the solution. Comparison with
available experimental data allowed us to produce the phase diagrams of both
bulk water and the aqueous solution as measurable in experiments. Given the
position of the liquid-liquid critical point in the solution as obtained from
our simulations, the experimental determination of the hypothesized
liquid-liquid critical point of water in aqueous solutions of salts appears
possible.Comment: 5 pages, 6 figures. Accepted for publication on the Journal of
Chemical Physics (2010)
