Cooperative Movement of H2O Molecules and Dynamic Behaviour of Dislocations in Ice Ih

Abstract

A new model of dislocations glide in ire Ih is proposed. In developing this model certain assumptions are made: (i) dislocations have a non-crystalline extended core, and (ii) transitions occur through cooperative movements of ?₂? molecules in the core of dislocations. A relation between the velocity ν _d of linear defects and shear stress τ or temperature T is obtained. This relation shows that ν _d varies linearly with τ at low values of τ and (or) T but varies more rapidly at higher stresses; this non-linearity is more pronounced the higher the temperature. Such results are in agreement with experimental data.