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O ice observed by neutron diffractionKomatsu, Kazuki*; Hattori, Takanori; Klotz, S.*; Machida, Shinichi*; Yamashita, Keishiro*; Ito, Hayate*; Kobayashi, Hiroki*; Irifune, Tetsuo*; Shimmei, Toru*; Sano, Asami; et al.
Nature Communications (Internet), 15, p.5100_1 - 5100_7, 2024/06
Times Cited Count：4 Percentile：72.77(Multidisciplinary Sciences)Hydrogen bond symmetrisation is the phenomenon where a hydrogen atom is located at the centre of a hydrogen bond. Theoretical studies predict that hydrogen bonds in ice VII eventually undergo symmetrisation upon increasing pressure, involving nuclear quantum effect with significant isotope effect and drastic changes in the elastic properties through several intermediate states with varying hydrogen distribution. Despite numerous experimental studies conducted, the location of hydrogen and hence the transition pressures reported up to date remain inconsistent. Here we report the atomic distribution of deuterium in DO ice using neutron diffraction above 100 GPa and observe for the first time the transition from a bimodal to a unimodal distribution of deuterium at around 80 GPa. At the transition pressure, a significant narrowing of the peak widths of 110 was also observed, attributed to the structural relaxation by the change of elastic properties.
Yamashita, Keishiro*; Komatsu, Kazuki*; Klotz, S.*; Fabelo, O.*; Fern
ndez-D
az, M. T.*; Abe, Jun*; Machida, Shinichi*; Hattori, Takanori; Irifune, Tetsuo*; Shimmei, Toru*; et al.
Proceedings of the National Academy of Sciences of the United States of America, 119(40), p.e2208717119_1 - e2208717119_6, 2022/10
Times Cited Count：7 Percentile：32.68(Multidisciplinary Sciences)Here we present the first elucidation of the disordered structure of ice VII, the dominant high-pressure form of water, at 2.2 GPa and 298 K from both single-crystal and powder neutron diffraction techniques. We reveal the three-dimensional atomic distributions from the maximum entropy method and unexpectedly find a ring-like distribution of hydrogen in contrast to the commonly-accepted discrete sites. In addition, total scattering analysis at 274 K clarified the difference in the intermolecular structure from ice VIII, the ordered counterpart of ice VII, despite an identical molecular geometry. Our complementary structure analyses robustly demonstrate the unique disordered structure of ice VII. Furthermore, these noble findings are related to the proton dynamics which drastically vary with pressure, and will contribute to an understanding of the structural origin of anomalous physical properties of ice VII under pressures.
Yamashita, Keishiro*; Komatsu, Kazuki*; Ohara, Takashi; Munakata, Koji*; Irifune, Tetsuo*; Shimmei, Toru*; Sugiyama, Kazumasa*; Kawamata, Toru*; Kagi, Hiroyuki*
High Pressure Research, 42(1), p.121 - 135, 2022/03
Times Cited Count：4 Percentile：47.58(Physics, Multidisciplinary)Komatsu, Kazuki*; Klotz, S.*; Nakano, Satoshi*; Machida, Shinichi*; Hattori, Takanori; Sano, Asami; Yamashita, Keishiro*; Irifune, Tetsuo*
High Pressure Research, 40(1), p.184 - 193, 2020/02
Times Cited Count：14 Percentile：66.86(Physics, Multidisciplinary)A new high pressure cells for neutron diffraction experiments using nano-polycrystalline anvil is presented. The cell design, off-line pressure generation tests and a gas-loading procedure for this cell are described. The performance is illustrated by powder neutron diffraction patterns of ice VII to 
82 GPa. We also demonstrate the feasibility of single crystal neutron diffraction experiments of Fe
O
at ambient conditions using this cell and discuss the current limitation and future developments.
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transition of iron by using EXAFSIshimatsu, Naoki*; Sata,Yusuke*; Maruyama, Hiroshi*; Watanuki, Tetsu; Kawamura, Naomi*; Mizumaki, Masaichiro*; Irifune, Tetsuo*; Sumiya, Hitoshi*
Hoshako, 28(1), p.3 - 11, 2015/01
no abstracts in English
Urakawa, Satoru*; Someya, Keiko*; Terasaki, Hidenori*; Katsura, Tomoo*; Yokoshi, Sho*; Funakoshi, Kenichi*; Utsumi, Wataru; Katayama, Yoshinori; Sueda, Yuichiro*; Irifune, Tetsuo*
Physics of the Earth and Planetary Interiors, 143-144, p.469 - 479, 2004/06
Times Cited Count：75 Percentile：76.75(Geochemistry & Geophysics)no abstracts in English
Isshiki, Maiko*; Irifune, Tetsuo*; Hirose, Kei*; Ono, Shigeaki*; Oishi, Yasuo*; Watanuki, Tetsu; Nishibori, Eiji*; Takata, Masaki*; Sakata, Makoto*
Nature, 427(6969), p.60 - 63, 2004/01
Times Cited Count：240 Percentile：96.12(Multidisciplinary Sciences)no abstracts in English
and HfO under high-temperature and high-pressureOtaka, Osamu*; Fukui, Hiroyuki*; Funakoshi, Kenichi*; Utsumi, Wataru; Irifune, Tetsuo*; Kikegawa, Takumi*
High Pressure Research, 22(1), p.221 - 226, 2002/01
Times Cited Count：30 Percentile：76.19(Physics, Multidisciplinary)no abstracts in English
under high pressure and high peratureOtaka, Osamu*; Fukui, Hiroyuki*; Kunisada, Taichi*; Fujisawa, Tomoyuki*; Funakoshi, Kenichi*; Utsumi, Wataru; Irifune, Tetsuo*; Kuroda, Koji*; Kikegawa, Takumi*
Physical Review B, 63(17), p.174108_1 - 174108_8, 2001/05
Times Cited Count：139 Percentile：97.09(Materials Science, Multidisciplinary)no abstracts in English
Utsumi, Wataru; Funakoshi, Kenichi*; Yagi, Naoto*; Urakawa, Satoru*; Otaka, Osamu*; Katsura, Tomoo*; Irifune, Tetsuo*; Inoue, Toru*; Uchida, Takeyuki*
Ganseki Kobutsu Kagaku, 30(2), p.100 - 101, 2001/03
no abstracts in English
Funakoshi, Kenichi*; Utsumi, Wataru; Otaka, Osamu*; Irifune, Tetsuo*; Inoue, Toru*; Ito, Eiji*; Katsura, Tomoo*; Kubo, Atsushi*; Hirose, Kei*; Ando, Junichi*; et al.
Ganseki Kobutsu Kagaku, 30(2), p.102 - 103, 2001/03
no abstracts in English
O
and implications for origin of ultra-deep diamond inclusionsIrifune, Tetsuo*; Miyashita, Minoru*; Inoue, Toru*; Ando, Junichi*; Funakoshi, Kenichi*; Utsumi, Wataru
Geophysical Research Letters, 27(21), p.3541 - 3544, 2000/11
Times Cited Count：40 Percentile：66.76(Geosciences, Multidisciplinary)no abstracts in English
by in situ X-ray diffraction and quench experimentsKuroda, Koji*; Irifune, Tetsuo*; Inoue, Toru*; Nishiyama, Norimasa*; Miyashita, Minoru*; Funakoshi, Kenichi*; Utsumi, Wataru
Physics and Chemistry of Minerals, 27(8), p.523 - 532, 2000/09
Times Cited Count：42 Percentile：77.54(Materials Science, Multidisciplinary)no abstracts in English
Utsumi, Wataru; Funakoshi, Kenichi*; Urakawa, Satoru*; Irifune, Tetsuo*; Tamura, Kozaburo*; Inui, Masanori*; Tsuji, Kazuhiko*; Shimomura, Osamu
Hoshako, 12(1), p.17 - 23, 1999/02
no abstracts in English
Utsumi, Wataru; Funakoshi, Kenichi*; Irifune, Tetsuo*
Sangyo To Denki, (554), p.11 - 16, 1998/11
no abstracts in English
SiO Determined by in Situ X-ray DiffractionIrifune, Tetsuo*; Nishiyama, Norimasa*; Kuroda, Koji*; Inoue, Toru*; Isshiki, Maiko*; Utsumi, Wataru; Funakoshi, Kenichi*; Urakawa, Satoru*; Uchida, Takeyuki*; Katsura, Tomoo*; et al.
Science, 279(5357), p.1698 - 1700, 1998/03
Times Cited Count：211 Percentile：93.54(Multidisciplinary Sciences)no abstracts in English
Irifune, Tetsuo*; Kuroda, Koji*; Nishiyama, Norimasa*; Inoue, Toru*; Funamori, Nobumasa*; Uchida, Takeyuki*; Yagi, Takehiko*; Utsumi, Wataru; Miyajima, Nobuyoshi*; Fujino, Kiyoshi*; et al.
Geophysical Monograph 101 (Properties of Earth and Planetary Materials at High Pressure and Temperature), p.1 - 8, 1998/00
no abstracts in English
