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en: Direct observation of pressure-induced amorphization of methane/ethane hydrates using Raman and infrared spectroscopy

en: Physical Chemistry Chemical Physics

ja: Physical Chemistry Chemical Physics


en: Pressure suppression of the excitonic insulator state in Ta2NiSe5 observed by optical conductivity

en: Physical Review B

ja: Physical Review B


en: Microscopic Structure and Binding Mechanism of the Corrosion-Protective Film of Oleylpropanediamine on Copper in Hot Water

en: The Journal of Physical Chemistry C

ja: The Journal of Physical Chemistry C


en: Measurements for diffusion coefficients of hydrogen in solids at high pressures using micro-Raman spectroscopy

ja: 顕微ラマン分光法による高圧力下における固体の水素拡散係数測定

en: We have developed an isotope analysis method to measure hydrogen isotope diffusion profiles in ice, hydroxides and related materials at high pressure. The calibration curves for quantitative analysis of deuterium in the materials were constructed using micro-Raman spectroscopy. Hydrogen-deuterium exchange diffusion experiments of ices VI, VII and Ca(OH)2 up to 20 GPa were carried out using micro-Raman spectroscopy and a diamond anvil cell. The pressure dependences of the diffusion coefficients of hydrogens in ice VII and Ca(OH)2 showed that hydrogen migration mechanisms changed drastically at high pressures. The changes in the mechanisms must be caused by strengthening of hydrogen bonds. This article describes the methodology and background for study of hydrogen diffusion in solids at high pressure.

ja: 高圧下での固体中の水素の自己拡散は，実験的な研究手法が限られており，その素過程については不明な点が多い．そこで，ダイヤモンドアンビルセル(DAC)と顕微ラマン分光法による同位体定量分析技術を組み合わせることによって，数万気圧を超える高圧力下での固体の水素拡散係数を測定する方法を開発した．この方法により，20 GPaまでの氷や水酸化物の水素拡散係数の圧力依存性を調べた．本論文においては，技術的な解説を行うのと同時に，いくつかの研究例についても紹介し，明らかになった高圧下での水素拡散の素過程や，高圧水素拡散係数の惑星科学研究への応用についても説明する．

en: Bunseki Kagaku

ja: 分析化学


en: Infrared and Raman Spectroscopic Study of Methane Clathrate Hydrates at Low Temperatures and High Pressures: Dynamics and Cage Occupancy of Methane


en: Rheological property of H2O ice VI inferred from its self-diffusion: implications for the mantle dynamics of large icy bodies

en: Icarus

ja: Icarus


en: Plutos ocean is capped and insulated by gas hydrates

en: Nature Geoscience

ja: Nature Geoscience


en: Self-diffusion of protons in H2O ice VII at high pressures: Anomaly around 10 GPa

en: The self-diffusion of ice VII in the pressure range of 5.5-17 GPa and temperature range of 400-425 K was studied using micro Raman spectroscopy and a diamond anvil cell. The diffusion was monitored by observing the distribution of isotope tracers: D2O and H2 (18)O. The diffusion coefficient of hydrogen reached a maximum value around 10 GPa. It was two orders of magnitude greater at 10 GPa than at 6 GPa. Hydrogen diffusion was much faster than oxygen diffusion, which indicates that protonic diffusion is the dominant mechanism for the diffusion of hydrogen in ice VII. This mechanism is in remarkable contrast to the self-diffusion in ice Ih that is dominated by an interstitial mechanism for the whole water molecule. An anomaly around 10 GPa in ice VII indicates that the rate-determining process for the proton diffusion changes from the diffusion of ionic defects to the diffusion of rotational defects, which was suggested by proton conductivity measurements and molecular dynamics simulations.

en: The Journal of Chemical Physics

ja: The Journal of Chemical Physics


en: Self-diffusion of polycrystalline ice Ih under confining pressure: Hydrogen isotope analysis using 2-D Raman imaging

en: Physics of the Earth and Planetary Interiors


en: A Peltier cooling diamond anvil cell for low-temperature Raman spectroscopic measurement

en: The Review of Scientific Instruments

ja: The Review of Scientific Instruments


en: Pressure-induced oligomerization of benzene at room temperature as a precursory reaction of amorphization

en: Oligomerization of benzene at high pressures up to 16 GPa was investigated at room temperature using an opposed-anvil type pressure apparatus. The recovered samples were analyzed using GC-MS to identify and quantify the products after the high-pressure experiments. Some structural isomers of benzene dimer as well as biphenyl, naphthalene, and terphenyl isomers were detected at pressures higher than 13 GPa. The molar yield of the polycyclic aromatic hydrocarbons increased concomitantly with increasing pressure, although benzene still remained. The oligomerization is likely to occur when the neighbor distance of the benzene molecules exceeds the threshold of the reaction distance. The oligomerization is regarded as a precursory phenomenon of the amorphization that occurs at higher pressure.


en: Near-infrared spectra of H2O under high pressure and temperature: Implications of a transition from proton tunneling to hopping states

en: The nature of protons in ice VII up to 368°C and 16GPa was investigated with synchrotron near-infrared spectroscopy. The absorption band of the first OH stretching overtone mode divided into doublet peaks above 5GPa at room temperature, suggesting that proton tunneling occurs at the overtone level. As the temperature increased, the doublet peaks gradually reduced to a singlet. This result implies that thermally activated protons hop between the two potential minima along the oxygen-oxygen axis. A pressure-temperature diagram for the proton state was constructed from the changing band shape of the overtone mode.

en: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy


en: Development of a Vacuum Collimator for a Silicon Drift Detector and Its Application to Light Element Analysis Under Atmospheric Condition

ja: SDD用真空コリメーターの開発と大気中での軽元素蛍光X線分析

en: X線分析の進歩

ja: X線分析の進歩


en: Formation of SiH4 and H2O by the dissolution of quartz in H2 fluid under high pressure and temperature

en: The American Mineralogist

ja: The American Mineralogist


en: Residual pressure distribution and visualization of mineral inclusions in corundum: application of photoluminescence spectroscopy in relation to sapphires from New England, New South Wales, Australia

en: The Australian Gemologist

ja: The Australian Gemologist


en: Imaging of internal stress around a mineral inclusion in a sapphire crystal: Application of micro-Raman and photoluminescence spectroscopy

en: Journal of Raman Spectroscopy

ja: Journal of Raman Spectroscopy


en: In situ spectroscopic observations of pressure-induced condensation of trimethylsilanol and behavior of dehydrated molecule water

en: Chemical Physics Letters

ja: Chemical Physics Letters


en: OH group behavior and pressure-induced amorphization antigorite examined under high pressure and temperature using synchrotron infrared spectroscopy


en: Chlorite - source of arsenic groundwater pollution in the Holocene aquifer of Banglades

en: Geochemical Journal

ja: Geochemical Journal


en: Proton migration in portlandite inferred from activation energy of self-diffusion and potential energy curve of OH bond

en: Physics and Chemistry of Minerals

ja: Physics and Chemistry of Minerals


en: Quantitative analysis of binary mineral mixtures using Raman microspectroscopy: Calibration curves for silica and calcium carbonate minerals and application to an opaline silica nodule of volcanic origin

en: We have developed a method for the quantitative analysis of binary mixtures of minerals using a common Raman microspectrometer having backscattering optical configuration (180° illumination) and a rotating sample stage. Using the averaged Raman spectra of mineral mixtures, the calibration curves of four mixtures of calcium carbonate and silica minerals—calcite and quartz, aragonite and calcite, quartz and cristobalite, and coesite and quartz—are constructed. The calibration curves express the correlation between the weight fraction and the relative intensities of the Raman bands intrinsic to the binary mixture. This technique can be used to map the phase distributions in one or two dimensions across an analytical sample surface and conduct quantitative analyses of samples containing inclusions with dimensions on the order of a few microns.<br>     As an example of the quantitative analysis using Raman microspectroscopy, the distribution of quartz and cristobalite in a silica nodule in volcanic rock from Akaze, Ishikawa prefecture is investigated. It is confirmed by X-ray diffraction, optical observation, and Raman mapping analysis that microquartz and opal-C are horizontally layered in the silica nodule. The line profile of the Raman spectra across the two regions reveals a sequential change in the weight ratio from quartz to cristobalite.

en: Journal of Mineralogical and Petrological Sciences


en: An induction heating diamond anvil cell for high pressure and temperature micro-Raman spectroscopic measurements

en: The Review of Scientific Instruments