Molecular dynamics simulations of alkali metal halides in supercritical water

The solvation structure of water molecules around alkali metal halides in a supercritical condition (647K and 217.55 atm pressure) has been investigated using classical molecular dynamics. Contact ion pairs are more stable than solvent assisted ion pairs. The hydration numbers of cations increase with the size of cations. For the anions, the hydration numbers decrease with increasing size of anions after Cl- Orientational distribution functions of solvent molecules are sharper for smaller ions. With an increase in the size of the anions, the water dipoles tilt more closely toward the ion oxygen vectors. (C) 2015 Elsevier B.V. All rights reserved.