SOLVATION STRUCTURE, HYDROGEN-BONDING, AND ION-PAIRING IN DILUTE SUPERCRITICAL AQUEOUS NACL MIXTURES

We review molecular dynamics simulations of infinitely dilute supercri tical aqueous NaCl solutions to determine the solvation structure and the solute-induced effect on water-water hydrogen bonding and report n ew simulation results on the extent of the ion pairing. Our simulation studies indicate that Na+ and Cl- ions as a pair or as isolated infin itely dilute ions form strong solvation structures in SCW, even though the water-water hydrogen bonding is not affected. Within the context of the models we are using, there is strong indication of a high degre e of Na+/Cl- ion pairing.