Spontaneous Raman scattering in mixtures of light and heavy water

The registration of spectra (in the range 10-4000 cm(-1)) of spontaneous Raman scattering in protium and deuterium water, as well as in its mixtures, is reported. The mixtures were prepared with different volume ratios of light and heavy water (from 5:1 to 1:9). As a result of taking into account the Bose factor in the low-wavenumber region, bands corresponding to the cluster translational modes of water were found. A change in the Raman shift of cluster modes depending on the isotopic composition of a mixture of liquids was recorded. In the wavenumber range 1000-1700 cm(-1), the manifestation of deformation modes of H2O, D2O, and HOD molecules was found in the Raman spectra. Stretching vibrations of mixtures of light and heavy water correspond to the wavenumber range of 2000-4000 cm(-1). The obtained dependences of the scattered radiation intensity were used to construct difference spectra, which made it possible to determine the content of D2O molecules in light water. The presented experimental results are of interest for diagnosing the presence of deuterium water in the biosphere and for analyzing nonlinear optical processes in water.