| 特集−水素結合− Rev. High Pressure Sci. Technol. 10-1,4-11(2000) |
| 高圧下での水素結合型構造相転移 Structural Phase Transition in Hydrogen-bond Crystals under High Pressure |
| 徳永 正晴 Masaharu TOKUNAGA |
| Recent development of studies on phase transitions in hydrogen-bond crystals are reviewed from a theoretical point of view. These crystals have been considered to display order-disorder type behaviors in phase tansitions at atomospheric pressure. After recent high pressure studies on these crystals，transition temperatures tend to zero kelvin with increasing pressure. If disordered arrangements of radicals in their directions hold down to zero kelvin，these facts are inconsistent with the third law of thermodynamics. A possibility of a displacive type is discussed in the mechanism of phase transition in these crystals. [hydrogen bond, ice rule, phase transition, isotope effect, displacive type] |
| 〒060-0810 札幌市北区北10条西8丁目 北海道大学理学研究科物理学専攻 Department of Physics, Graduate School of Science, Hokkaido University, Sapporo, 060-0952 |
| 特集−水素結合− Rev. High Pressure Sci. Technol. 10-1,12-17(2000) |
| 水素結合型強誘電体KH2PO4とKD2PO4の圧力効果 Pressure Effect on Hydrogen-Bond Ferroelectrics KH2PO4 and KD2PO4 |
| 遠藤将一* 出口 潔** Shoichi ENDO Kiyoshi DEGUCHI |
| Temperature dependences of the dielectric constant along the ferroelectric c-axis have been measured at various pressures up to 7.9GPa in KH2PO4 and KD2PO4. The vanishing of the ferroelectric state has been observed at 1.7 GPa in KH2PO4 and at 6.3 GPa in KD2PO4. The Curie constant C of KH2PO4 is almost independent of pressure. On the other hand, that of KD2PO4 above 4 GPa decreases about three fourths of that at atmospheric pressure. The crossover of the order-disorder type to the displacive one under high pressure is discussed on the mechanism of phase transition to explain these experimental results of KD2PO4. [high-pressure, hydrogen-bond ferroelectric, KH2PO4, KD2PO4, dielectric constant, phase transition] |
| *〒560-8531 豊中市待兼山町1-3 大阪大学極限科学研究センター Research Center for Materials Science at Extreme Conditions, Osaka University, Toyonaka, Osaka 560-8531 **〒437-8555 袋井市2200-2 静岡理工科大学物質科学科 Department of Materials Science, Shizuoka Institute of Science and Technology, Fukuroi, Shizuoka 437-8555 |
| 特集−水素結合− Rev. High Pressure Sci. Technol. 10-1,18-25(2000) |
| 水素結合をもつ硫化水素固体の高圧相 High-pressure Phase Studies of Solid Hydrogen Sulfide having Hydrogen Bonds |
| 清水 宏晏 Hiroyasu SHIMIZU |
| This article reviews recent developments in high-pressure phase studies of H2S by Raman scattering, x-ray and neutron diffractions, FT infrared absorption, and first-principles calculation. At room temperature, solid H2S shows many phase transitions under high pressures; - I - (8 GPa) -I'- (11 GPa) - IV - (30 GPa) - V - (46 GPa) - VI -. The characteristic features of each phase transition are presented and discussed by considering the behaviors of hydrogen bondings and molecular rotations. [ DAC, hydrogen sulfide, Raman scattering, x-ray diffraction, neutron diffraction, infrared absorption, first-principles calculation, phase transition, hydrogen bond, molecular rotation, molecular dissociation ] |
| 〒501-1193 岐阜市柳戸1-1 岐阜大学工学部電気電子工学科 (大学院 環境エネルギーシステム専攻) Department of Electrical and Electronic Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193 |
| 特集−水素結合− Rev. High Pressure Sci. Technol. 10-1,26-32(2000) |
| ハロゲン化水素の水素結合とその圧力依存性 Hydrogen Bonding of Hydrogen Halides and Its Pressure Dependence |
| 池田 隆司 寺倉 清之 Takashi IKEDA Kiyoyuki TERAKURA |
| The nature and stability of the disordered phase I and the ordered phase III of solid hydrogen bromide underpressure were investigated using the ab initio molecular dynamics method. A detailed study of the response to pressure of the orientational distribution and the orientational and vibrational dynamics in disordered phase showed that phase I can be described as a rotator phase with fluctuating hydrogen bonds up to pressures well over 10 GPa. We predict that the disorder at higher densities leads to cooperative proton-transfer dynamics. The pressure dependence of stretching modes in phase I and lattice modes in phase III was also investigated and compared well with experimental data. [hydrogen bromide, hydrogen bond, structural phase transition, proton transfer, molecular dynamics] |
| 〒305-8562 茨城県つくば市東1-1-4 産業技術融合領域研究所 National Institute for Advanced Interdisciplinary Research, 1-1-4 Higashi, Tsukuba, Ibaraki 305-8562 |
| 特集−水素結合− Rev. High Pressure Sci. Technol. 10-1,33-41(2000) |
| 四角酸などの有機酸の水素結合と誘電特性 Dielectric Properties of Hydrogen-bonded Organic Materials |
| 守友 浩 Yutaka Moritomo |
| Dielectric properties of hydrogen-bonded materials, 1) squaric acid with two-dimensional network, 2) hydrogen-bonded chain systems and 3) isolated systems, are discussed. In squaric acid, we have found two types of phase change, that is, conventional order-disorder-type dielectric transition and deformation of the proton-potential from double- to single-well type. In the case of one-dimensional system, we have found the kink-type defects due to the degeneracy of the hydrogen-bonded chain. In the isolated system, we have observed a variety of dielectric transitions, and will discuss probability of the proton-tunneling. [dielectric properties, hydrogen-bonded materials, order-disorder-type transition, proton-potential, kink-soliton, proton-tunneling, quantum paraelectricity] |
| 〒464-8601 名古屋市千種区不老町名古屋大学理工科学総合研究センター総合基礎材料科学 CIRSE, Nagoya University, Chikusaku, Nagoya 464-8601 |
| 特集−水素結合− Rev. High Pressure Sci. Technol. 10-1,42-49(2000) |
| 分子結晶における電子−プロトン連動と機能性 Electron-proton Cooperation in Molecular Crystals |
| 三谷 洋興 北川 宏 中筋 一弘* Tadaoki MITANI Hiroshi KITAGAWA Kazuhiro NAKASUJI |
| The cooperation of electron and proton in organic systems has a large potentiality for the creation of new molecular functions in molecular crystals. In this article, the electron-proton-cooperation in charge transfer crystals is reviewed, particularly focusing on the ir spectroscopy of the phase transition in quinhydrone charge-transfer crystals under high pressures. As an example of the electron-proton cooperation at ambient pressure, the metal-insulator phase transition observed in [Pd(H2-xEDAG) (HEDAG)]TCNQ (EDAG= ethylenediamino-glyoxime, x = ca. 0.7) is reported. [charge transfer, proton transfer, electron-proton cooperation, H-bond, phase transition, quinhydrone, [Pd(H2-xEDAG) (HEDAG)]TCNQ, ir spectroscopy, high pressure] |
| 〒923-1292 石川県能美郡辰口町旭台 1-1 北陸先端科学技術大学院大学 Japan Advanced Institute of Science and Technology, Tatsunokuchi-cho, Ishikawa 923-1292 *〒560-0043 豊中市待兼山町 1-1 大阪大学理学研究科 Osaka University, Machikaneyama, Toyonaka, Osaka, 560-0043 |
| 論説 Rev. High Pressure Sci. Technol. 10-1,50-55(2000) |
| 超臨界重合の工業化に想う −高圧重合の歴史から眺めたテフロン製造プロセス− Industrialization of Supercritical High Pressure Polymerization in Teflon Production |
| 小郷 良明 Yoshiaki OGO |
| The historical development of polymerization under high pressure has been reviewed and the possibility of an industrial application of high pressure polymerization has been discussed in our previous works on radical polymerization at high pressure. Taking recent environmental concerns into consideration and the significant advancement in the technology of high temperature and high pressure, the synthesis of fluoropolymers in supercritical carbon dioxide, especially DeSimone's process, is discussed considering the chemical kinetics at the critical point with emphasis on supercritical carbon dioxide as an excellent reaction media. [High pressure polymerization, Supercritical fluid, Carbon dioxide, Teflon, Critical point] |
| 〒761-0301 高松市林町2217-43 高温高圧流体技術研究所 Research Institute for Solvothermal Technology (RIST), 2217-43 Hayashi, Takamatsu, Kagawa 761-0301 |
| 研究の最前線から Rev. High Pressure Sci. Technol. 10-1,56-61(2000) |
| SPring-8のダイヤモンド分光器 Synthetic Diamond Monochromator at SPring-8 |
| 山本 雅貴 熊坂 崇 石川 哲也 Masaki YAMAMOTO Takashi KUMASAKA Tetsuya ISHIKAWA |
| This paper describes the possibility of utilizing a synthetic diamond as a new optical element in the third-generation synchrotron radiation source SPring-8. The development of the synthetic diamond allows for the branching of the low emmitance undulator source, and opens a new multi-color. At SPring-8, RIKEN Beamline I (BL45XU) is the first branched undulator beamline, which consists of two experimental stations, protein crystallography (PX) and small-angle X-ray scattering (SAXS). The branched beams are generated by a transparent diamond crystal. The PX branch of RIKEN Beamline I has been designed based on the trichromatic concept to optimize the multi-wavelength anomalous diffraction (MAD) method data collection. This concept involves three kinds of intensity data sets with three different wavelengths being taken quasi-simultaneously for the single protein crystal without changing any settings on the diamond trichromator. [SPring-8, Beamline, diamond, monochromator, protein crystallography, MAD-method, trichromator] |
| 〒679-5148 兵庫県佐用郡三日月町光都1丁目1-1 理化学研究所 播磨研究所 構造生物物理研究室 Structural Biophysics Laboratory, RIKEN, 1-1-1 Kouto, Mikaduki, Sayo, Hyogo 679-5148 |
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