Fundamental problems
Important information about intra- and intermolecular interactions in water can be obtained from spectroscopic characteristics of water, in particular, from the spectra of water Raman scattering. Until now, the structure of liquid water is not clear, and no complete model of vibrational processes in liquid water, which could adequately explain mechanisms of formation of water Raman spectral bands, has been established. Besides that, there are serious contradictions in conceptions about resonance interactions of vibrations in water molecules. The problem of contribution of Fermi resonance (resonance between overtone of bending vibrations and symmetric valence vibrations) to formation of valence band of water Raman spectrum still remains topical. Water Raman spectrum is rather complicated, and it consists of a number of bands with different intensities, widths, and shapes.