Suppression of X-ray-induced dissociation of H2O molecules in dense ice under pressure

Hiroshi Fukui; Nozomu Hiraoka; Naohisa Hirao; Katsutoshi Aoki; Yuichi Akahama

doi:10.1038/srep26641

Suppression of X-ray-induced dissociation of H2O molecules in dense ice under pressure

Sci Rep. 2016 May 25:6:26641. doi: 10.1038/srep26641.

Authors

Hiroshi Fukui¹, Nozomu Hiraoka², Naohisa Hirao³, Katsutoshi Aoki⁴, Yuichi Akahama¹

Affiliations

¹ Center for Novel Material Science under Multi-Extreme Conditions, Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Hyogo 678-1297, Japan.
² SPring-8 Taiwan Beamline Office, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
³ Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan.
⁴ Geochemical Research Center, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.

Abstract

We investigated molecular dissociation induced by 10-keV X-ray irradiation in dense ice at pressures up to 40 GPa at 300 K. The dissociation yield estimated from the oxygen K-edge X-ray Raman spectra, showed that the molecular dissociation was enhanced up to 14 GPa and gradually suppressed on further compression to 40 GPa. The molecular dissociation was detected for a rather narrow pressure span of 2-40 GPa by the X-ray spectroscopy. The pressure variation of the dissociation yield was similar to that observed in the electric conductivity of ice VII and likely interpreted in terms of proton mobility.

Publication types

Research Support, Non-U.S. Gov't