Dynamical structure of water in aqueous solutions of LiCl, NaCl, and KCl by low-frequency Raman scattering: Comparison between the multiple random telegraph model and Cole-Cole relaxation

Abstract

Depolarized low-frequency Raman spectra of aqueous solutions of LiCl, NaCl, and KCl have been investigated over a wide concentration range. The spectra were analyzed with one relaxation mode and two damped harmonic oscillators. We applied two types of relaxation model: the multiple random telegraph (MRT) model and the Cole-Cole-type relaxation. Each relaxation time becomes longer than that of liquid water in both relaxation models. Structure making (Li, Na) and structure breaking (K) effects were concluded from a fitting parameter corresponding to the modulation speed in the MRT model.