The role of the so-called cooperativity of H bonding, and of the dichotomously branching transfer of protons, was studied on the basis of a dynamic square lattice model. It was shown that the extended positive (H3O+) and negative (OH-) ionic defects could be described by 2-dimensional topological solitons. It was concluded that the 2-dimensional non-linear dynamic model which was suggested here was an interesting new object. Its local topological equivalence to the 3-dimensional hexagonal structure permitted the study of those non-linear collective excitations in ice which did not migrate in the bulk of a crystal. In particular, the dynamic process of the creation of a pair of ionic defects, and the dependence of the defect density upon temperature, could be studied within the framework of this model. These studies were expected to be much more suitable for the understanding of H-bonded 3-dimensional networks than was a crude 1-dimensional soliton model. Finally, the present model allowed for 2-dimensional soliton solutions with a finite height of the Peierls-Nabarro relief in the continuum limit. Such a phenomenon could not exist in the corresponding 1-dimensional kink-containing model.

A.V.Zolotaryuk, A.V.Savin, E.N.Economou: Solid State Ionics, 1995, 77, 28-33