p-Aminobenzoic acid polymorphs under high pressures

Rapid development of in situ experimental techniques provides researchers with new opportunities to model geological processes, which take place deep in the Earth&#8217;s interior. Raman spectroscopy is considered a powerful analytical tool for investigation of the samples subjected to high pressures in a diamond anvil cell, since in such experiments phase assemblages can be determined in real time using measured Raman spectra.In this study, we describe experimental methods for in situ observation and spectroscopic analysis of fluids and minerals, which constitute environment for diamond growth, at the upper mantle pressure conditions. Experiments were conducted in the externally heated, &#8220;piston-cylinder&#8221; type diamond anvil cell at pressures exceeding 6 GPa and temperatures up to 600 degree C. Phase relationships and fluid speciation were monitored during experiments to reconstruct the environment and mechanism of inclusions formation. Compared to other analytical tools, commonly used in combination with diamond anvil cell apparatus, Raman spectroscopy offers several advantages, such as short sample preparation time, non-destructive characterization of the phases observed in the sample chamber and relatively short measurement time.This work was supported by grant No. 20-77-00079 from the Russian Science Foundation.

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High Pressure in situ Micro-Raman Spectroscopy of Ge-Sn System Synthesized in a Laser Heated Diamond Anvil Cell

10.1063/1.3606347 ◽

2011 ◽

Cited By ~ 1

Author(s):

Y. A. Sorb ◽

N. Subramanian ◽

T. R. Ravindran ◽

P. Ch. Sahu ◽

Alka B. Garg ◽

...

Keyword(s):

Raman Spectroscopy ◽

High Pressure ◽

Diamond Anvil Cell ◽

Micro Raman Spectroscopy ◽

Diamond Anvil ◽

Laser Heated

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Pressure-induced phase transition of La2Zr2O7 and La0.5Gd1.5Zr2O7 pyrochlore

RSC Advances ◽

10.1039/c9ra03438b ◽

2019 ◽

Vol 9 (33) ◽

pp. 18954-18962 ◽

Cited By ~ 4

Author(s):

Jingjing Niu ◽

Xiang Wu ◽

Haibin Zhang ◽

Shan Qin

Keyword(s):

Phase Transition ◽

Raman Spectroscopy ◽

High Pressure ◽

Diamond Anvil Cell ◽

X Ray Diffraction ◽

X Ray ◽

Diamond Anvil

In situ high-pressure experiments on La2Zr2O7 and La0.5Gd1.5Zr2O7 have been carried out at up to approximately 40 GPa using synchrotron X-ray diffraction and Raman spectroscopy combined with a diamond anvil cell technique.

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Examining the structural changes in Fe2(CO)9 under high external pressures by Raman spectroscopy

Canadian Journal of Chemistry ◽

10.1139/v07-096 ◽

2007 ◽

Vol 85 (10) ◽

pp. 866-872 ◽

Cited By ~ 2

Author(s):

Muhieddine Safa ◽

Zhaohui Dong ◽

Yang Song ◽

Yining Huang

Keyword(s):

Raman Spectroscopy ◽

High Pressure ◽

Diamond Anvil Cell ◽

Structural Changes ◽

High Pressures ◽

Metal Carbonyl ◽

In Situ Raman Spectroscopy ◽

Metal Metal ◽

Diamond Anvil ◽

Pressure Phase

Pressure-induced structural changes in di-iron nonacarbonyl [Fe2(CO)9] were examined by in situ Raman spectroscopy with the aid of a diamond anvil cell. Our results indicate that Fe2(CO)9 undergoes a pressure-induced phase transformation at about 0.9 GPa. Upon further compression, another structural transformation is identified at 7 GPa. In the low-pressure phase below 0.9 GPa, the π back-bonding between metal and carbonyl increases with increasing pressure. In the high-pressure phase above 7 GPa, the combination of high-pressure and laser irradiation induces a change in structure from Fe2(CO)9 to Fe2(CO)8. Fe2(CO)8 appears to adopt a structure with C2v rather than D3d or D2h symmetry. The metal–metal bond is gradually weakened under high pressures, and Fe2(CO)8 eventually decomposes by breaking the Fe–Fe bond when compressed up to 17.7 GPa.Key words: metal carbonyl, Raman spectroscopy, high pressure, diamond anvil cell.

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The thermal conductivity of the Earth's core and implications for its thermal and compositional evolution

National Science Review ◽

10.1093/nsr/nwaa303 ◽

2020 ◽

Author(s):

Kenji Ohta ◽

Kei Hirose

Keyword(s):

Thermal Conductivity ◽

High Pressure ◽

Thermal History ◽

Diamond Anvil Cell ◽

High Pressures ◽

Iron Alloys ◽

Compositional Evolution ◽

The Earth ◽

Diamond Anvil ◽

High Pressures And Temperatures

Abstract Precise determinations of the thermal conductivity of iron alloys at high pressures and temperatures are essential for understanding the thermal history and dynamics of the metallic cores of the Earth. We review relevant high-pressure experiments using a diamond-anvil cell and discuss implications of high core conductivity for its thermal and compositional evolution.

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PHASE TRANSITION IN LAYERED PEROVSKITE LIKE MANGANATE Ca3Mn2O7 UNDER HIGH PRESSURE

International Journal of Modern Physics B ◽

10.1142/s0217979201007117 ◽

2001 ◽

Vol 15 (18) ◽

pp. 2491-2497 ◽

Cited By ~ 1

Author(s):

J. L. ZHU ◽

L. C. CHEN ◽

R. C. YU ◽

F. Y. LI ◽

J. LIU ◽

...

Keyword(s):

Crystal Structure ◽

High Pressure ◽

Diamond Anvil Cell ◽

The Other ◽

Layered Perovskite ◽

X Ray Diffraction ◽

Two Phase ◽

X Ray ◽

Diamond Anvil

In situ high pressure energy dispersive X-ray diffraction measurements on layered perovskite-like manganate Ca 3 Mn 2 O 7 under pressures up to 35 GPa have been performed by using diamond anvil cell with synchrotron radiation. The results show that the structure of layered perovskite-like manganate Ca 3 Mn 2 O 7 is unstable under pressure due to the easy compression of NaCl-type blocks. The structure of Ca 3 Mn 2 O 7 underwent two phase transitions under pressures in the range of 0~35 GPa. One was at about 1.3 GPa with the crystal structure changing from tetragonal to orthorhombic. The other was at about 9.5 GPa with the crystal structure changing from orthorhombic back to another tetragonal.

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The Fluorescence of Diamond and Raman Spectroscopy at High Pressures Using a New Design of Diamond Anvil Cell

Applied Spectroscopy ◽

10.1366/000370273774333353 ◽

1973 ◽

Vol 27 (5) ◽

pp. 377-381 ◽

Cited By ~ 58

Author(s):

D. M. Adams ◽

S. J. Payne ◽

K. Martin

Keyword(s):

Raman Spectroscopy ◽

Diamond Anvil Cell ◽

High Pressures ◽

Fluorescence Emission ◽

Type I ◽

High Pressure Cell ◽

Scattering Geometry ◽

Infrared And Raman Spectroscopy ◽

Bond Stretching ◽

Diamond Anvil

A new design of diamond anvil high pressure cell suitable for use in infrared and Raman spectroscopy is described. Its performance is demonstrated with particular reference to the pressure dependence of the infrared spectrum of K2PtCl6 and the Raman spectrum of W(CO)6. In contrast to earlier reports, in which forward scattering geometry was used, this design of cell is shown to be very suitable for Raman use in the 180° excitation mode. However, severe limitations are imposed by the fluorescence emission of diamond and of sapphire. Conditions under which the cell can be used for Raman work are summarized. New fluorescence and Raman features are reported for diamond. In particular, a band at 1730 cm−1 is characteristic of type I stones and may be due to C to N bond stretching at defect centers.

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Reliability of multigrain indexing for orthorhombic polycrystals above 1 Mbar: application to MgSiO3 post-perovskite

Journal of Applied Crystallography ◽

10.1107/s1600576716018057 ◽

2017 ◽

Vol 50 (1) ◽

pp. 120-130 ◽

Cited By ~ 1

Author(s):

Christopher Langrand ◽

Nadège Hilairet ◽

Carole Nisr ◽

Mathieu Roskosz ◽

Gábor Ribárik ◽

...

Keyword(s):

Experimental Data ◽

High Pressure ◽

Grain Orientation ◽

Diamond Anvil Cell ◽

Polycrystalline Material ◽

Data Set ◽

Grain Orientations ◽

Diamond Anvil ◽

Diffraction Peaks

This paper describes a methodology for characterizing the orientation and position of grains of an orthorhombic polycrystalline material at high pressure in a diamond anvil cell. The applicability and resolution of the method are validated by simulations and tested on an experimental data set collected on MgSiO3 post-perovskite at 135 GPa. In the simulations, ∼95% of the grains can be indexed successfully with ∼80% of the peaks assigned. The best theoretical average resolutions in grain orientation and position are 0.02° and 1.4 µm, respectively. The indexing of experimental data leads to 159 grains of post-perovskite with 30% of the diffraction peaks assigned with a 0.2–0.4° resolution in grain orientation. The resolution in grain location is not sufficient for in situ analysis of spatial relationships at high pressure. The grain orientations are well resolved and sufficient for following processes such as plastic deformation or phase transformation. The paper also explores the effect of the indexing parameters and of experimental constraints such as rotation range and step on the validity of the results, setting a basis for optimized experiments.

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