Multisite Disordered Structure of Ice VII to 20 GPa

R. J. Nelmes; J. S. Loveday; W. G. Marshall; G. Hamel; J. M. Besson; S. Klotz

doi:10.1103/PhysRevLett.81.2719

Multisite Disordered Structure of Ice VII to 20 GPa

R. J. Nelmes, J. S. Loveday, W. G. Marshall, G. Hamel, J. M. Besson, and S. Klotz

Phys. Rev. Lett. 81, 2719 – Published 28 September 1998

Abstract

Neutron diffraction measurements on ice VII and ice VIII at pressures up to 20 GPa provide direct evidence of multisite disorder of both oxygen and deuterium atoms in $D_{2} O$ ice VII, and give the magnitudes of the site separations. An O-D distance and D-Ô-D angle closest to those found in ice VIII are obtained with oxygen sites displaced along $〈 111 〉$ directions. Such displacements imply an H-bond geometry significantly different from that found in ice VIII, and this may have implications for the centering transition to ice X.

Received 5 May 1997

DOI:https://doi.org/10.1103/PhysRevLett.81.2719

Authors & Affiliations

R. J. Nelmes, J. S. Loveday, and W. G. Marshall^*

Department of Physics and Astronomy, The University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom

G. Hamel¹, J. M. Besson², and S. Klotz²

¹Département des Hautes Pressions, Université Pierre et Marie Curie, 4 place Jussieu, 75252 Paris, France
²Physique des Milieux Condensés (CNRS UMR 7602), Université Pierre et Marie Curie, 4 place Jussieu, 75252 Paris, France