A facet of recent ice sciences

Of prime interest in the numerous studies on water, an important substance to mankind and all other living systems, may be its chemical, physical, biological or geological characteristics but underlying all these is a basic structural problem. One of the important questions that still remains unanswered in this field is: why ordinary ice keep its proton-disordered state down to the lowest temperature. We found that the slowing down of water re-orientational motion at low temperatures leads to freezing of the disordered state in the ice crystal at around 110 K. This was the origin of the deviation of the crystal from the third law of thermodynamics. Doping by a particular kind of impurity recovered the mobility of the molecule to exhibit a long-awaited ordering transition at 72 K. The dopant dramatically accelerated the motion of water molecules to change the crystal from a non-equilibrium frozen-in disordered state to the equilibrium one within our experimental time. New steps in ice sciences and procedures used in these experiments are reviewed briefly. The structure and some properties of the low-temperature ordered phase, designated as ice XI, are described.