title: Suppression of X-ray-induced dissociation of H2O molecules in dense ice under pressure.
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.
authors.affiliation: 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.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fukui
authors.affiliation: SPring-8 Taiwan Beamline Office, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
authors.forename: Nozomu
authors.initials: N
authors.lastname: Hiraoka
authors.affiliation: Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan.
authors.forename: Naohisa
authors.initials: N
authors.lastname: Hirao
authors.affiliation: Geochemical Research Center, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Aoki
authors.affiliation: 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.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Akahama