An insight into liquid water networks through hydrogen bonding halide anion: Stimulated Raman scattering.

We have studied the interaction between water molecules and halide anions and acquired the influence of concentration by the spontaneous Raman spectrum. The results agreed well with the previous researches. To explore further, the stimulated Raman scattering of a halide-water binary solution is measured to study the nature of the hydrogen bonding between water molecules and halogen anions. Under the effect of laser-induced plasma, the OH stretching vibration spectra of aqueous solutions of halogen ions pretty exhibit different trend compared with that of spontaneous Raman spectrum. The frequency shifts of water OH vibration show different values and directions with adding different halide anions. The red shift of F^-- and Cl^--water molecule clusters is due to the process of charge transfer, whereas the blue shift of Br^-- and I^--water molecule cluster is due to polarization effect without charge transfer. The results demonstrate that F^- and Cl^- slightly weaken the hydrogen bond (HB), whereas Br^- and I^- enhance HB in the water cluster. The decrease of concentration of halogen ions aqueous solution can weaken the effect on the HB. [ABSTRACT FROM AUTHOR]