Depolarization ratio studies on liquid water

Accurate laser Raman band shapes and depolarization ratios have been obtained for the stretching bands of H2O and D2O between 0 and 100°C. The depolarized band shapes differ from those previously measured using mercury arc instruments in that the low frequency maxima of H2O (3259 cm−1) and D2O (2380 cm−1) are more pronounced, especially in D2O at temperatures close to the melting point. The depolarization ratio spectra display approximately temperature-invariant behavior at 3230 and 3630 cm−1 for H2O and at 2300 and 2670 cm−1 for D2O; depolarization ratios at the extreme high and low frequency band edges are increasing functions of temperature and those in the middle are decreasing functions of temperature. The depolarization ratio spectra have an over-all sigmoidal shape. These results have been interpreted in terms of a simple model which contains elements of the continuum approach of Schiffer and Hornig and the mixture model of Walrafen.