Four-photon Raman spectroscopy of intermolecular vibrations in water solutions of electrolytes

The influence of electrolyte concentration on the water libration spectrum was studied by four-photon polarization spectroscopy. The results were comp ared with the data on stretching O-H vibrations observed in spontaneous Ram an spectroscopy in water solutions of electrolytes, and a qualitative coinc idence of these results was found. It is shown that the weakening of hydrog en bonds at low electrolyte concentrations and the strengthening of couplin g between water molecules and ions at high concentrations shift the librati on resonances to high and low wavenumbers, respectively. Copyright (C) 2000 John Wiley & Sons, Ltd.