Modulated phases and proton centring in ice observed by X-ray diffraction up to 170?GPa

Paul Loubeyre, René LeToullec, Elodie Wolanin, Michel Hanfland and Daniel Hausermann
Additional contact information
Paul Loubeyre: Laboratoire Etats Extrmes Statiques
René LeToullec: CNRS and Universit Paris 6
Elodie Wolanin: CNRS and Universit Paris 6
Michel Hanfland: ESRF
Daniel Hausermann: ESRF

Nature, 1999, vol. 397, issue 6719, 503-506

Abstract: Abstract Because of its open hydrogen-bonded structure, ice shows many structural changes between different crystalline forms under high pressure. Crystallographic studies of these transitions have been pursued largely by neutron scattering, which allows the positions of the hydrogen atoms to be identified1,2. Such studies have previously been extended to pressures of up to 20?GPa, which is however insufficient to permit the investigation of ice X, a ‘symmetric ice’ in which the protons are thought to reside midway between the oxygen atoms3,4,5. So far, information about ice X has therefore come from indirect methods such as infrared6,7 or Brillouin8 spectroscopy. Here we show that single-crystal X-ray diffraction is able to reveal the signature of hydrogen-bond symmetrization. The 111 reflection can be assigned to the hydrogen atoms alone, and we can measure it up to 170?GPa in a diamond anvil cell. This diffraction line (normalized against the intensity of the 222 line, which is due mostly to oxygen atoms) indicates that the proton centring in ice X occurs from about 60 to 150?GPa; at this latter pressure the intensity increases sharply, signalling a further structural change. At lower pressures, we see ice VII ordering in a sequence of spatially modulated phases between 2.2 and 25?GPa, which suggests an analogy with the incommensurate phases of the frustrated Ising model9.

Date: 1999
References: Add references at CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.nature.com/articles/17300 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:397:y:1999:i:6719:d:10.1038_17300

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/17300

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().