Depolarized light scattering of heavy water, and hydrogen bond dynamics

The depolarized Rayleigh scattering of heavy water was measured from 700C down to -130C. The spectra were analysed and show a low frequency component. Both the intensity and the width of this line are temperature dependent. The characteristic time associated with the width has an Arrhenius behaviour with an activation energy of 2.5 kcal mol-1. The intensity has a quadratic shape with a maximum around 500C. These results are interpreted as a manifestation of the hydrogen-bond dynamics and propose a mechanism for the breaking of H-bonds through the librational movements. Comparisons are made with theoretical models and molecular dynamics simulations. (author)