Dynamic Nature of High-Pressure Ice VII.

Starting from Shannon's definition of dynamic entropy, we propose a theory to describe the rare-event-determined dynamic states in condensed matter and their transitions and apply it to high-pressure ice VII. A dynamic intensive quantity named dynamic field, rather than the conventional thermodynamic intensive quantities such as temperature and pressure, is taken as the controlling variable. The dynamic entropy versus dynamic field curve demonstrates two dynamic states in the stability region of ice VII and dynamic ice VII. Their microscopic differences were assigned to the dynamic patterns of proton transfer. This study puts a similar dynamical theory used in earlier studies of glass models on a simpler and more fundamental basis, which could be applied to describe the dynamic states of more realistic condensed matter systems.