特集−分子性固体− Rev. High Pressure Sci. Technol. 10-3,187-193(2000) |
Li の圧力誘起構造相転移の圧力誘起構造相転移 Phase Transition of Li under High Pressure |
森 嘉久 財部 健一 Yoshihisa MORI Kenichi TAKARABE |
Lithium starts to lose its high reflectivity
at 19 GPa and turns black like graphite.
The color change is reversible Lithium starts
to lose its high reflectivity at 19 GPa and
turns black like graphite. The color change
is reversible with large hysteresis. The
black color does not change to 200 GPa. At
75 GPa, it is not transparent to visible
with large hysteresis. The black color does
not change to 200 GPa. At 75 GPa, it is not
transparent to visible light, nor to a laser
beam at 0.785 eV, nor to a laser beam at
0.12 eV. This behavior means it is either
a semicon- light, nor to a laser beam at
0.785 eV, nor to a laser beam at 0.12 eV.
This behavior means it is either a semicon-ductor
with a gap below 0.12 eV, or a semi-metal
like graphite although such behavior could
arise from multi- ductor with a gap below
0.12 eV, or a semi-metal like graphite although
such behavior could arise from multi-internal
reflections as a result of the anisotropy
of the permittivity in the single crystal.
There is no vibron peak internal reflections
as a result of the anisotropy of the permittivity
in the single crystal. There is no vibron
peak from a lithium molecule up to 150 GPa.
The Raman spectrum at 160 GPa has a broad
peak around 600 cm from a lithium molecule
up to 150 GPa. The Raman spectrum at 160
GPa has a broad peak around 600 cm-1 on a on a large background, which is
considered to be caused by the fluorescence
of diamond. large background, which is considered
to be caused by the fluorescence of diamond. [Lithium, phase transition, molecular solid, DAC, Raman scattering Lithium, phase transition, molecular solid, DAC, Raman scattering] |
〒700-0005 岡山理科大学理学部基礎理学科岡山理科大学理学部基礎理学科 Department of Applied Science, Okayama Univrsity of Science, Ridai 1-1, Okayama 700-0005 |
特集−分子性固体− Rev. High Pressure Sci. Technol. 10-3,194-199(2000) |
酸素の金属化と超伝導 Metallization and Superconductivity in Oxygen under High Pressure |
清水克哉 Katsuya SHIMIZU |
Oxygen is popular but unique among diatomic
molecules in that it behaves magnetically
at low temperature.Under high pressure, however,
we expect the insulator-metal transition.
This expectation has been suggested by measuring
its optical reflectivity[1] under high pressures
around 95 GPa (1 Mbar). A new structural
transition[2] is considered to be accompanied
by metallization. Obviously, the most direct
method of detecting metallization is to measure
the electrical resistance. We measured the
resistance of oxygen at pressures of over
100 GPa[3] and identified the metallic state
from a change in the slope of dR/dT . In this paper, we present our findings
on the superconducting transition of oxygen
under high pressures of around 100 GPa and
at temperatures of under 0.6 K. The superconducting
transition is indicated by a drop in resistance.
We confirmed this by observing the magnetic
field dependence of the drop and by detecting
the Meissner demagnetization signal. [oxygen, diatomic molecule, high pressure, metallization, molecular dissociation, superconductivity,electrical resistance] |
〒560- 8531 豊中市待兼山町1- 3 大阪大学大学院基礎工学研究科 Graduate School of Engineering Science, Osaka University 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 |
特集−分子性固体− Rev. High Pressure Sci. Technol. 10-3,200-207(2000) |
固体CX4(X=H, F, Cl)の圧力誘起構造相転移 Pressure-induced Structural Phase Transition of CX4(X = H, F, Cl) Solid |
川村春樹 赤浜裕一 Haruki KAWAMURA Yuichi AKAHAMA |
A molecular solid consisting of low-Z elements
tends to crystallize into a plastic crystal,
in which molecules rotate freely on lattice
points. By the application of pressure, rotation
of molecules freezes and the order-disorder
transition takes place. The structural phase
transition of these molecular crystals has
been frequently studied by spectrographic
techniques. The recent progress of synchrotron
radiation sources has enabled us to investigate
crystal structures of low-Z materials through
x-ray diffraction analysis. In this article,
pressure-induced structural phase transition
of CX4 (X = H, F, Cl) solids is reviewed. [molecular crystal, plastic crystal, phase transition, x-ray diffraction, Raman spectrum] |
〒678-1297 兵庫県赤穂郡上郡町光都3-2-1 姫路工業大学理学部 Faculty of Science, Himeji Institute of Technology, 3-2-1 Kouto, Kamigori, Ako-gun, Hyogo 678-1297 |
特集−分子性固体− Rev. High Pressure Sci. Technol. 10-3,208-213(2000) |
ヨウ化スズの高圧力下における構造相転移 Phase Transition in Tintetraiodide at High Pressure |
佐藤 恭子 浜谷 望 Kyoko SATO Nozomu HAMAYA |
High-pressure studies of tintetraiodide SnI4
are reviewed. Recent x-ray diffraction study
has shown that SnI4 undergoes successive
phase transition from an insulator crystalline
phase (I ;Pa3 ) to a metallic crystalline phase (II)
at 7 GPa, to the amorphous state at about
15 GPa, and to a non-molecular crystalline
phase (III ;Fm3m) at 61 GPa. The crystal structure of phase
III has been determined to be substitutional
disordered structure in which both iodine
and tin atoms are randomly located at the
fcc sites. [tintetraiodide, metallization, amorphization, molecular dissociation] |
〒112-8610 東京都文京区大塚2-1-1 お茶の水女子大学大学院
人間文化研究科 複合領域科学専攻 Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1, Ohtsuka, Bunkyo-ku, Tokyo 112-8610 |
特集−分子性固体− Rev. High Pressure Sci. Technol. 10-3,214-220(2000) |
高圧下における C6I6 の結晶および分子構造 Crystal Structure and Molecular Structure of C6I6 under High Pressure |
中山敦子 藤久裕司 青木勝敏 Atsuko NAKAYAMA Hiroshi FUJIHISA Katsutoshi AOKI |
Hexaiodobenzene (C6I6) is one of the organic monomolecular crystals
indicating pressure-induced metallization.
Our recent studies on x-ray powder diffraction
experiments and Raman scattering spectral
measurements of C6I6 under high pressure are reviewed: pressurization
in a preliminary process of the pressure-induced
metallization causes six iodine atoms to
be suspended from a benzene-ring accompanied
by a decrease in intermolecular I-I distances.
It follows from this that charge transfer
interaction is mainly generated by the overlapping
of a 5pz orbital of iodine and a π-orbital
of carbon among the adjacent molecules which
accelerates the molecular deformation. [hexaiodobenznen, pressure-induced metallization, x-ray powder diffraction, Raman spectroscopy, Fermi resonance] |
〒305-8565 茨城県つくば市東1-1 物質工学工業技術研究所 極限反応部 高圧化学グループ National Institute of Materials and Chemical Research, 1-1 Higashi, Tsukuba, Ibaraki 305-8565 |
解説 Rev. High Pressure Sci. Technol. 10-3,221-227(2000) |
液体リンの1次相転移 A First-Order Phase Transition in Liquid Phosphorus |
片山芳則 Yoshinori KATAYAMA |
In this article, a recent discovery of a
liquid-liquid phase transition in phosphorus
is reviewed. By an in situ X-ray diffraction
method, we have observed an abrupt pressure-induced
structural change between a low-pressure
molecular liquid and a high-pressure polymeric
liquid at about 1 GPa. Experimental results
strongly support that it is a first-order
transition between two thermodynamically
stable liquid phases. This is the first in-situ observation of such a transition in a liquid
of pure substance. [phosphorus, liquid-liquid transition, diffraction, synchrotron radiation, pressure] |
〒679-5148 兵庫県佐用郡三日月町光都1-1-1
日本原子力研究所 放射光科学研究センター Synchrotron Radiation Research Center, 1-1-1 Kouto, Mikazuki, Sayo, Hyogo 679-5148, Japan |
解説 Rev. High Pressure Sci. Technol. 10-3,228-234(2000) |
高圧下でのX線を用いた構造解析と格子振動解析 Structure and Lattice Vibration Analyses under High Pressure using X-ray Diffraction and X-ray Absorption Techniques |
吉朝 朗 Akira YOSHIASA |
The single-crystal x-ray diffraction method
using a diamond anvil cell is an important
method for crystal structure determination
under high-pressure. The x-ray absorption
spectroscopy under high-pressure provides
the detailed information on local structure
around particular kinds of atoms, even if
the crystal structure is unknown. Extended
x-ray absorption fine structure (EXAFS) spectroscopy
is useful as a probe of vibration dynamics
under pressure. An anharmonic effective pair
potential can be investigated using the EXAFS
technique. The knowledge of the local structure
is of primary importance for the understanding
of the complicated physical properties of
solid solutions. The change of the spin state
of the Co4+ ion in the perovskite-type Sr(Co, Mn)O3 solid solution whose magnetic properties
varies according to the compositions have
been explained based on the local structure
analysis. [x-ray diffraction method, x-ray absorption spectroscopy, XANES, EXAFS, structure determination, local structure, effective pair potential, lattice vibration, solid solution, spin state] |
〒560-0043 豊中市待兼山町1-1 大阪大学大学院理学研究科宇宙地球科学専攻 Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka 560-0043 |
解説 Rev. High Pressure Sci. Technol. 10-3,235-242(2000) |
高圧力実験装置入門−光学窓(金属ガスケットシール法)− A Guide for High Pressure Experements −Optical Window ( Metal Gasket Method )− |
網田富士嗣・梶本興亜 Fujitsugu AMITA Okitsugu KAJIMOTO |
The effective and reliable sealing with metal
gaskets for a high-pressure optical
window
is described. A practical method for
polishing
a window plug is explained. We have
developed
a pair of jigs to shape Au gaskets,
which
are explained in detail. The shaping
of Au
gaskets with the jigs is also demonstrated.
A window plug gripping jigs to fasten
the
high-pressure optical window is also
introduced.
[high-pressure optical window, metal gasket] |
〒606-8502 京都市左京区北白川追分町 京都大学大学院理学研究科化学専攻 Division of Chemistry, Graduated School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 |
実験ワンポイント Rev. High Pressure Sci. Technol. 10-3,243-244(2000) |
氷の準安定融解曲線の測定 Measurement of the Metastable Melting Curves of Ice Phases |
三島 修 Osamu MISHIMA |
We have developed an experimental method
using emulsions to measure the metastable
melting curves of ice phases at low
temperatures
and high pressures. For the melting
experiment,
we constructed a special hydraulic
press
with two oil-pressure systems, and
reduced
error in the sample pressure. [high pressure, pressure control, melting, phase transition, liquid water, ice] |
〒305-0044 つくば市並木 1-1 科学技術庁無機材質研究所 National Institute for Research in Inorganic Materials, 1-1 Namiki, Tsukuba 305-0044 |
〒606-0805
京都市左京区下鴨森本町 15 (財)生産開発科学研究所内
日本高圧力学会事務局
Tel (075)721-0376 Fax (075)723-9629
koatsu@mbox.kyoto-inet.or.jp