phases of ice come in pairs
To date, fifteen phases of ice have been discovered. Equilibrium phases are shown below on the left, while on the right, some metastable phases, which will eventually revert to an equilibrium phase, are added. Twelve of these phases occur in pairs consisting of a hydrogen bond disordered phase and a lower-temperature ordered phase: Ih and XI, III and IX, V and XIII, VII and VIII and XII and XIV.
The disordered phase contains the water oxygens in nearly the same
positions as the fully ordered phase, but the orientations of
hydrogens are disordered. The animation on the right shows the origin
of the hydrogen bond disorder. You can see that many different unit
cells of ice can be built in which each water is fully satisfied with
four hydrogen bonds.
Our research examines the phase transitions between members of these ordered/disordered pairs. We have successfully predicted 5 of the 6 transitions, and experiments are still underway for the last one. We have predicted how local hydrogen bond disorder can account for small shifts of the waters from the average positions. We have also examined the behavior of charged defects, like H+ and OH- in ice.
This research has been supported by the National Science Foundation.
some relevant publications
- Jer-Lai Kuo and Sherwin J. Singer, ``Graph invariants for periodic systems: towards predicting physical properties from the hydrogen bond topology of ice'', Phys. Rev.E67(1):016114 (2003).
- Sherwin J. Singer, Jer-Lai Kuo, Tomas K. Hirsch, Chris Knight, Lars Ojamäe and Michael L. Klein, ``Hydrogen bond topology and the ice VII/VIII and Ih/XI proton ordering phase transitions'', Phys.Rev.Lett. 94(13):135701 (2005).
- Chris Knight and Sherwin J. Singer, ``Prediction of a phase transition to a hydrogen bond ordered form of ice VI'', J.Phys.Chem. B109(44):21040 (2005).
- Chris Knight, Sherwin J. Singer, Jer-Lai Kuo, Tomas K. Hirsch, Lars Ojamäe and Michael L. Klein, ``Hydrogen bond topology and the ice VII/VIII and Ih/XI proton ordering phase transitions'', Phys.Rev. E73(5):056113 (2006).
- Chris Knight and Sherwin J. Singer, ``Tackling the problem of hydrogen bond order and disorder'', Physics and Chemistry of Ice (Proceedings of the 11th International Conference on the Physics and Chemistry of Ice), ed., Werner F. Kuhs (Royal Soc. of Chemistry, 2007), p.329.
- Chris Knight and Sherwin J. Singer, ``Theoretical study of a hydroxide ion within the ice-Ih lattice'', Physics and Chemistry of Ice (Proceedings of the 11th International Conference on the Physics and Chemistry of Ice), ed., Werner F. Kuhs (Royal Soc. of Chemistry, 2007), p.339.
- Chris Knight and Sherwin J. Singer, ``Hydrogen bond ordering in ice V and the transition to ice XIII'', J. Chem. Phys. 129(16):164513 (2008).
- Chris Knight and Sherwin J. Singer, ``Site disorder in ice VII arising from hydrogen bond fluctuations'', J. Phys. Chem. A113(45):12433 (2009).