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A Study of Near-and Super-Critical Fluids Using diamond anvil cell and in-Situ FT-IR Spectroscopy

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Acta Geologica Sinica(English Edition) 2000年第2期74卷 412-417页

作者： HU Shumin ZHANG Ronghua ZHANG Xuetong Open Research Lab.of Geochemical Kinetics Chinese Academy of Geological Sciences26 Baiwanzhuang RoadBeijing100037

The phase relation and solution structure of water and NaCl aqueous solution have been observed and examined by using the hydrothermal diamond anvil cell (HDAC) at elevated temperatures and pressures and the in situ FT-IR spectroscopy. The temperature of observations ranges from 25 to 850°C and the pressure up to 10 or 30 kb. At first, we observed the phase transition process from halite+liquid+vapour (H+L+V) to L+H, then to L (or supercritical fluid, SCF), and another path: H+L+V→L+V→L (or SCF) in heating process. By means of the visual microscope, the authors found that in the L+V immiscibility field L+V exhibits an ordered structure, i.e. a large visual cluster of solvent around ions. The liquid phase is manifested by vapour bubbles. When phase transitions are observed, the authors examined their infrared spectra by using the FT-IR microscopy simultaneously. In the case of the phase transition from liquid (L) to liquid + vapor (L+V) immisciblity field of NaCl solutions, a sudden change (strong frequency shift) of infrared spectra of the aqueous solution is observed near the critical temperature of water as the temperature is raised from 25 to 650°C. The frequency of the maximum intensity of OH symmetric and asymmetric vibration varies with respect to temperature. The sharp peak of the OH stretching vibration of the maximum intensity appears in an interval from 300 to 400°C. It is indicated that the hydrogen bonding network is weakened and broken at last near the critical point of water, which causes the aqueous solution to become more associated. Besides, a pressure indicator (a mineral or compound) was introduced to the HDAC.

关键词： diamond anvil cell critical state in situ IR microscopy

How far away are accurate equations of state determinations? Some issues on pressure scales and non-hydrostaticity in diamond anvil cells

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Matter and Radiation at Extremes 2016年第4期1卷 224-236页

作者： Lei Liu Yan Bi National Key Laboratory of Shock Wave and Detonation Physics Institute of Fluid PhysicsChina Academy of EngineeringMianyang621900China Department of Earth Science Uppsala UniversityUppsalaSE75236Sweden

The equations of state(EOSs)of materials are the cornerstone of condensed matter physics,material science,and ***,acquiring an accurate EOS in diamond anvil cell(DAC)experiments continues to prove problematic because the current lack of an accurate pressure scale with clarified sources of uncertainty makes it difficult to determine a precise pressure value at high pressure,and nonhydrostaticity affects both the volume and pressure *** study will discuss the advantages and drawbacks of various pressure scales,and propose an absolute pressure scale and correction methods for the effects of *** the end of this paper,we analyze the accuracy of the determined EOS in the DAC experiments we can achieve to date.

关键词： Equation of state Pressure scale Nonhydrostaticity effect diamond anvil cell

Synthesis of black phosphorus structured polymeric nitrogen

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Chinese Physics B 2020年第10期29卷 406-410页

作者： Ying Liu Haipeng Su Caoping Niu Xianlong Wang Junran Zhang Zhongxue Ge Yanchun Li Xi'an Modern Chemistry Research Institute Xi'an 710065China Key Laboratory of Materials Physics Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China

Since the discoveries of polymeric nitrogen, named cg-N (2004), LP-N (2014), HLP-N (2019), another polymorph named black phosphorus nitrogen (BP-N) was synthesized at high-pressure-high-temperature conditions. The narrow existing pressure region and similar synthesized pressure of BP-N compared with cg-N indicate that the stable energy and enthalpy of formation of these two structures are close to each other, which was confirmed by our theoretical calculation. In order to obtain the pressure region of BP-N phase, pure N2 and TiN/Pb + N2 precursors were used for laser-heating high pressure experiments in diamond anvil cell (DAC), and the phase identity was examined by Raman and XRD mapping. BP-N can be synthesized in the pressure range of 130 GPa to 140 GPa with the assistance of heating absorber. With the decrease of the pressure, BP-N can be quenched to ~ 40 GPa. The synthesizing pressure–temperature and the stable pressure region of BP-N are important for further exploration of BP-N and its kinetic and thermal dynamic relationship with other polymeric nitrogen, especially cg-N.

关键词： high pressure and high temperature energetic materials polymeric nitrogen diamond anvil cell

Ruby fluorescence pressure scale: Revisited

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Chinese Physics B 2013年第5期22卷 402-406页

作者：柳雷毕延徐济安 National Key Laboratory of Shock Wave and Detonation Physics Institute of Fluid PhysicsChina Academy Of Engineering Physics

Effect of non-hydrostatic stress on X-ray diffraction in a diamond anvil cell （DAC） is studied. The pressure gradient in the sample chamber leads to the broadening of the diffraction peaks, which increase with the hkl index of the crystal. It is found that the difference between the determined d-spacing compressive ratio d/do and the real d-spacing compressive ratio dr/do is determined by the yield stress of the pressure transmitting media （if used） and the shear modulus of the sample. On the basis of the corrected experiment data of Mao et al. （MXB86）, which was used to calibrate the most widely used ruby fluorescence scale, a new relationship of ruby fluorescence pressure scale is corrected, i.e., P = （1904/9.827）[（1 ＋ △λ/λ0）9.827 - 1].

关键词： non-hydrostatic stress ruby fluorescence pressure scale diamond anvil cell

Shock temperature and reflectivity of precompressed H2O up to 350 GPa:Approaching the interior of planets

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Chinese Physics B 2018年第12期27卷 405-412页

作者： Zhi-Yu He Hua Shu Xiu-Guang Huang Qi-Li Zhang Guo Jia Fan Zhang Yu-Chun Tu Jun-Yue Wang Jun-Jian Ye Zhi-Yong Xie Zhi-Heng Fang Wen-Bing Pei Si-Zu Fu Shanghai Institute of Laser Plasma CAER P.O.Box 800-229Shanghai201800China IFSA Collaborative Innovation Center Shanghai Jiaotong UniversityShanghai 200240China Institute of Applied Physics and Computational Mathematics Beijing 100088China Center for High Pressure Science and Technology Advance Research Beijing 100094China

Using a combination of static precompression and laser-driven shock compression, shock temperature and reflectivity of H2O have been measured up to 350 GPa and 2.1×10~4 K. Here, two calibration standards were applied to enhance temperature measurement reliability. Additionally, in temperature calculations, the discrepancy in reflectivity between active probe beam wavelength and self-emission wavelength has been taken into account to improve the data’s *** water’s temperature–pressure data are in very good agreement with our quantum molecular dynamics model,suggesting a superionic conductor of H2O in the icy planets’ deep interior. A sluggish slope gradually approaching Dulong–Petit limit at high temperature was found at a specific heat capacity. Also, high reflectivity and conductivity were observed at the same state. By analyzing the temperature–pressure diagram, reflectivity, conductivity and specific heat comprehensively at conditions simulating the interior of planets in this work, we found that as the pressure rises, a change in ionization appears; it is supposedly attributed to energetics of bond-breaking in the H2O as it transforms from a bonded molecular fluid to an ionic state. Such molecular dissociation in H2O is associated with the conducting transition because the dissociated hydrogen atoms contribute to electrical properties.

关键词： high temperature measurement equation of state of water laser-driven shock diamond anvil cell

Thickness-dependent phase transition and optical behavior of MoS2 films under high pressure

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Nano Research 2018年第2期11卷 855-863页

作者： Xuerui Cheng Yuanyuan Li Jimin Shang Chuansheng Hu Yufen Ren Miao Liu Zeming Qi School of Physics and Electronic Engineering Zhengzhou University of Light Industry Zhengzhou China National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei China Energy Technologies Area Lawrence Berkeley National Laboratory Berkeley USA

We report the Raman and photoluminescence spectroscopic analysis of layered MoS2 under hydrostatic pressure up to 30 GPa. Unlike previous studies, throughout this work, a special treatment is applied to submerge monolayer, bilayer, multilayer （-200 layers）, and bulk MoS2 samples directly into silicone oil without a supporting substrate in a diamond anvil cell, thereby eliminating possible interference from substrate-film contact. A thickness-dependent trend is observed for the 2Hc-to-2Ha phase transition： The transition pressure increases from 19.0 to 25.6 GPa as the system thickness is reduced from bulk to multilayer MoS2; a further decrease in thickness to the bilayer structure increases the transition pressure to - 36 GPa, as predicted theoretically. This exceeds our measured pressure range, indicating the weakening of interlayer repulsive interactions as the MoS2 film thickness is reduced. Our experiment also reveals a monotonic trend of Raman peak shifting vs. film thickness under applied pressure, suggesting that the Raman vibration modes are more responsive to external pressure in thinner films. The photoluminescence emission peak of the monolayer MoS2 exhibits a blue shift under applied pressure at the rate of 23.8 ***-1. These results show that the structural and optical properties of MoS2 can be effectively modified by applying hydrostatic pressure.

关键词： molybdenum disulfide high pressure Raman spectroscopy photoluminescence diamond anvil cell

Investigating the thermal conductivity of materials by analyzing the temperature distribution in diamond anvils cell under high pressure

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Chinese Physics B 2022年第4期31卷 219-224页

作者： Caihong Jia Min Cao Tingting Ji Dawei Jiang Chunxiao Gao State Key Laboratory of Superhard Materials Jilin UniversityChangchun 130000China College of Mathematics and Physics Inner Mongolia University for NationalitiesTongliao 028043China

Investigating the thermal transport properties of materials is of great importance in the field of earth science and for the development of materials under extremely high temperatures and ***,it is an enormous challenge to characterize the thermal and physical properties of materials using the diamond anvil cell(DAC)*** the present study,a steady-state method is used with a DAC and a combination of thermocouple temperature measurement and numerical analysis is performed to calculate the thermal conductivity of the *** this end,temperature distributions in the DAC under high pressure are *** propose a three-dimensional radiative-conductive coupled heat transfer model to simulate the temperature field in the main components of the DAC and calculate in situ thermal conductivity under high-temperature and high-pressure *** proposed model is based on the finite volume *** obtained results show that heat radiation has a great impact on the temperature field of the DAC,so that ignoring the radiation effect leads to large errors in calculating the heat transport properties of ***,the feasibility of studying the thermal conductivity of different materials is discussed through a numerical model combined with locally measured temperature in the *** article is expected to become a reference for accurate measurement of in situ thermal conductivity in DACs at high-temperature and high-pressure conditions.

关键词： thermal conductivity heat radiation effect temperature field diamond anvil cell

High-pressure synchrotron x-ray diffraction and Raman spectroscopic study of plumbogummite

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Chinese Physics B 2018年第1期27卷 541-546页

作者：康端巫翔袁冠黄圣轩牛菁菁高静秦善 Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of Education School of Earth and Space SciencesPeking University State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences

PbA13（PO4）2（OH,H20）6, an important environmental mineral, is in-situ studied by synchrotron x-ray diffraction （XRD） and Raman scattering combined with diamond anvil cells （DACs） at pressures up to - 11.0 GPa and room temper- ature. The XRD results indicate that plumbogummite does not undergo a phase transition between 0 GPa and 10.9 GPa. Moreover, the c axis is more compressible than the a axis, revealing its anisotropic behavior. The pressure-volume data are fitted to the third-order Birch-Murnaghan equation of state to yield the plumbogummite bulk modulus K0 of 68（ I ） GPa and KU of 6.1. The [PO4]3 and [HPO4]2 Raman vibrational modes exhibit scale nearly linearly as a function of pressure. The [PO4]3 stretching modes are generally more sensitive to pressure than the bending modes. The Grfineisen parameters range from -0.07 to 1.19, with an arithmetic mean of approximately 0.39.

关键词： plumbogummite equation of state Grfineisen parameter diamond anvil cell

Raman scattering from highly-stressed anvil diamond

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Chinese Physics B 2021年第1期30卷 407-411页

作者： Shan Liu Qiqi Tang Binbin Wu Feng Zhang Jingyi Liu Chunmei Fan Li Lei Institute of Atomic and Molecular Physics Sichuan UniversityChengdu 610065China Key Laboratory of High Energy Density Physics and Technology(Ministry of Education) Sichuan UniversityChengdu 610065China

The high-frequency edge of the first-order Raman mode of diamond reflects the stress state at the culet of anvil, and is often used for the pressure calibration in diamond anvil cell(DAC) experiments. Here we point out that the high-frequency edge of the diamond Raman phonon corresponds to the Brillouin zone(BZ) center Γ point as a function of pressure. The diamond Raman pressure gauge relies on the stability of crystal lattice of diamond under high stress. Upon the diamond anvil occurs failure under the uniaxial stress(197 GPa), the loss of intensity of the first-order Raman phonon and a stressdependent broad Raman band centered at 600 cm^(-1) are observed, which is associated with a strain-induced local mode corresponding to the BZ edge phonon of the L1 transverse acoustic phonon branch.

关键词： diamond anvil cell Raman scattering pressure calibration Brillouin zone