Self-Diffusion in Liquid Water to −31°C

The self-diffusion coefficient of water is reported to −31°C, where the activation energy reaches 11 kcal/mole compared with 4.5 kcal/mole at 25°C. The similarity of the temperature dependence of the fraction of broken hydrogen bonds, as inferred from Raman and infrared data, and the diffusion coefficient over the entire liquid range forms the basis of empirical support of the dominant role of hydrogen bonding in the fundamental diffusion mechanism.