Fast and slow dynamics of hydrogen bonds in liquid water

We study hydrogen-bond dynamics in liquid water at low temperatures using molecular dynamics simulations. We find that bond lifetime (``fast dynamics'') has Arrhenius temperature dependence. We also calculate the bond correlation function and find that the correlation time (``slow dynamics'') shows power-law behavior. This power-law behavior, as well as the decay of the bond correlations, is consistent with the predictions of the mode-coupling theory. The correlation time at the lowest temperature studied shows deviation from power-law behavior that suggests continuity of dynamic functions between the liquid and glassy states of water at low pressure.