HR: 0800h
AN: P31A-0953    [Abstracts]
TI: Theoretical investigation of the structural properties of high-density H2O-ice
AU: * Umemoto, K
EM: umemoto@cems.umn.edu
AF: Department of Chemical Engineering and Materials Science and Minnesota Supercomputing Institute, University of Minnesota, 421 Washington Ave SE, Minneapolis, MN 55455 United States
AU: Wentzcovitch, R M
EM: wentzcov@cems.umn.edu
AF: Department of Chemical Engineering and Materials Science and Minnesota Supercomputing Institute, University of Minnesota, 421 Washington Ave SE, Minneapolis, MN 55455 United States
AB: At extreme conditions not easily realized in the laboratory, such as low T, long observational time scales, and high P produced by static or dynamic compression, H2O-ice displays amazing structural behavior. Computer simulations can help us to understand this unusual material and we have investigated ice VIII intensively using first principles methodologies. This is a prototypical form of high-pressure ice consisting of two interpenetrating hydrogen-bond networks. Here we clarify several of its unusual properties under pressure: the correlated non-linear behavior of various physical quantities, instabilities responsible for amorphization, and dipole re-ordering. The relationship between ice VIII-like and ice XI-like structures, two prototypical forms of high and low-pressure ice, is also clarified. Research supported by NSF/EAR 0230319 and 013533 (COMPRES).
DE: 6020 Ice
DE: 3924 High-pressure behavior
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting