Structural dynamics of aqueous salt solutions

The addition of ions to water has a dramatic effect on the structure of liquid. It also showed in the conventional infrared absorption and Raman spectroscopic studies that the addition of salt to water directs to a severe disruption of the hydrogen-bonded structure of the liquid and to the formation of solvation shells. For most ions, the coordination numbers of the hydration shells are known, and the mean distances between ions and the water molecules in the first and second hydration shells have been identified. It is showed that ions have a very limited effect on the hydrogen-bounded structure of liquid water outside the first solvation shell. This results implies that the macroscopic properties of salt solutions have to be explained from different effects such as effect of ions on the linear absorption spectrum, viscosity of liquid water, orientational and translational dynamics of water. The dynamics of aqueous salt solutions have also been studied with experimental and theoretical techniques such as nuclear magnetic resonance (NMR), low-frequency Raman scattering, dielectric relaxation spectroscopy Rayleigh, Brillouin scattering, and, molecular dynamics simulations.