Spontaneous Raman scattering in mixtures of light and heavy water

Abstract 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 H 2 O, D 2 O, 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 D 2 O 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.