Electric field of Ions in solution probed by hyper-Rayleigh scattering.

The electric field of dissolved ions accounts for the narrow spike at zero frequency shift, with the polarization signature of a polar longitudinal collective mode, in the high resolution hyper-Rayleigh light scattering (HRS) spectrum for liquid water and other polar solvents. This peak in the HRS spectrum probes both the structure factor and the fluctuation time for the ion charge density in solution. The experimental results for KCl-D(2)O solutions are consistent with the Debye-Huckel charge structure factor and determine the diffusion coefficient and static local field factor.