Raman light scattering studies of the depolarized low frequency region of water and aqueous solutions

Raman spectra of the depolarized Rayleigh wing (20–350 cm−1) for water and aqueous solutions have been recorded in digital form and recast in the R2(?) format as described previously. Studies of water, aqueous fluoride, and perchlorate suggest that the weak peak at 191 cm−1 has its origin in the hydrogen bonded water structure. Temperature and isotopic substitution (D2O, H2 18O) measurements support this conclusion. Anisotropic ions and molecules such as NO3−, CN−, and acetone superimpose an intense librational peak on the water spectrum.