A new approach to the dynamics of hydrogen bond network in liquid water

The relation between topology and rearrangement dynamics of the hydrogen bond network (HBN) in the supercooled liquid water is investigated by using molecular dynamics (MD) calculation and examining topological indices. We have found that there is very strong correlation among certain pairs of hydrogen bonds. HBN is shown to be represented by an ‘‘undirected’’ graph. Topology and rearrangement dynamics of HBN are then simply described in terms of the network defects and their motions. Based on this fact, a new lattice dynamic model is proposed. The model shows that spontaneous heterogeneous hydrogen bond rearrangement occurs even when the network structure is homogeneous.