scholarly journals The Structure of Ferroselite, FeSe2, at Pressures up to 46 GPa and Temperatures down to 50 K: A Single-Crystal Micro-Diffraction Analysis

Crystals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 289 ◽  
Author(s):  
Barbara Lavina ◽  
Robert Downs ◽  
Stanislav Sinogeikin
Keyword(s):  
Single Crystal ◽  
Low Temperatures ◽  
Diamond Anvil Cell ◽  
Structural Changes ◽  
High Pressures ◽  
Structural Instability ◽  
Crystal Structure Analysis ◽  
Ambient Conditions ◽  
Diamond Anvil

We conducted an in situ crystal structure analysis of ferroselite at non-ambient conditions. The aim is to provide a solid ground to further the understanding of the properties of this material in a broad range of conditions. Ferroselite, marcasite-type FeSe2, was studied under high pressures up to 46 GPa and low temperatures, down to 50 K using single-crystal microdiffraction techniques. High pressures and low temperatures were generated using a diamond anvil cell and a cryostat respectively. We found no evidences of structural instability in the explored P-T space. The deformation of the orthorhombic lattice is slightly anisotropic. As expected, the compressibility of the Se-Se dumbbell, the longer bond in the structure, is larger than that of the Fe-Se bonds. There are two octahedral Fe-Se bonds, the short bond, with multiplicity two, is slightly more compressible than the long bond, with multiplicity four; as a consequence the octahedral tetragonal compression slightly increases under pressure. We also achieved a robust structural analysis of ferroselite at low temperature in the diamond anvil cell. Structural changes upon temperature decrease are small but qualitatively similar to those produced by pressure.

scholarly journals The Structure of Ferroselite, FeSe2, at Pressures Upto 46 GPa and Temperatures Down to 50 K: ASingle-Crystal Micro-Diffraction Analysis

2018 ◽  
Author(s):  
Barbara Lavina ◽  
Robert T Downs ◽  
Stanislav Sinogeikin
Keyword(s):  
Low Temperatures ◽  
Diamond Anvil Cell ◽  
Structural Changes ◽  
High Pressures ◽  
Structural Instability ◽  
Crystal Structure Analysis ◽  
Temperature Decrease ◽  
Ambient Conditions ◽  
Diamond Anvil

We conducted an in-situ crystal structure analysis of ferroselite at non-ambient conditions. The aim is to provide a solid ground to further the understanding of the properties of this material in a broad range of conditions. Ferroselite, marcasite-type FeSe2, was studied under high pressures up to 46 GPa and low temperatures, down to 50 K using single-crystal microdiffraction techniques. High pressure and low temperatures were generated using a diamond anvil cell and a cryostat. We found no evidences of structural instability in the explored P-T space. The deformation of the orthorhombic lattice is slightly anisotropic. As expected, the compressibility of the Se-Se dumbbell, the longer bond in the structure, is larger than that of the Fe-Se bonds. Less obvious is the behavior of the octahedral bonds, the shorter bond is the most compressible determining a small increase in the octahedron distortion with pressure. We also achieved a robust structural analysis of ferroselite at low temperature in the diamond anvil cell. Structural changes upon temperature decrease are small but qualitatively similar to those produced by pressure.

scholarly journals Studying weak interactions in crystals at high pressures: when hardware matters

2018 ◽  
Vol 74 (5) ◽  
pp. 613-619 ◽  
Author(s):  
Boris A. Zakharov ◽  
Zoltan Gal ◽  
Dyanne Cruickshank ◽  
Elena V. Boldyreva
Keyword(s):  
Data Processing ◽  
Single Crystal ◽  
Diamond Anvil Cell ◽  
High Pressures ◽  
Weak Interactions ◽  
Structural Models ◽  
Processing Strategies ◽  
Diamond Anvil

The quality of structural models for 1,2,4,5-tetrabromobenzene (TBB), C6H2Br4, based on data collected from a single crystal in a diamond anvil cell at 0.4 GPa in situ using two different diffractometers belonging to different generations have been compared, together with the effects of applying different data-processing strategies.

In situ Raman spectroscopic technique for high-pressure studies of mineral and fluid inclusions formation 

2021 ◽  
Author(s):  
Nadezda Chertkova ◽  
Anna Spivak ◽  
Egor Zakharchenko ◽  
Yuriy Litvin ◽  
Oleg Safonov ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Diamond Anvil Cell ◽  
High Pressures ◽  
Rapid Development ◽  
Spectroscopic Technique ◽  
Diamond Growth ◽  
Russian Science ◽  
Geological Processes ◽  
Diamond Anvil

<p>Rapid development of <em>in situ</em> experimental techniques provides researchers with new opportunities to model geological processes, which take place deep in the Earth’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.</p><p>In this study, we describe experimental methods for <em>in situ</em> 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, “piston-cylinder” 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.</p><p>This work was supported by grant No. 20-77-00079 from the Russian Science Foundation.</p>

p-Aminobenzoic acid polymorphs under high pressures

RSC Advances ◽  
2014 ◽  
Vol 4 (30) ◽  
pp. 15534-15541 ◽  
Author(s):  
Tingting Yan ◽  
Kai Wang ◽  
Defang Duan ◽  
Xiao Tan ◽  
Bingbing Liu ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Diamond Anvil Cell ◽  
High Pressures ◽  
Aminobenzoic Acid ◽  
Aminobenzoic Acids ◽  
Diamond Anvil

The effect of high pressure on two forms (α, β) of p-aminobenzoic acids (PABA) is studied in a diamond anvil cell using in situ Raman spectroscopy.

Laboratory-based x-ray computed tomography for 3D imaging of samples in a diamond anvil cell in situ at high pressures

2020 ◽  
Vol 91 (9) ◽  
pp. 093703
Author(s):  
Kenji Ohta ◽  
Tatsuya Wakamatsu ◽  
Manabu Kodama ◽  
Katsuyuki Kawamura ◽  
Shuichiro Hirai
Keyword(s):  
Computed Tomography ◽  
3D Imaging ◽  
Diamond Anvil Cell ◽  
High Pressures ◽  
X Ray ◽  
Diamond Anvil ◽  
X Ray Computed

High-quality structures at high pressure? Insights from inclusions in diamonds

2016 ◽  
Vol 231 (8) ◽  
Author(s):  
Ross J. Angel ◽  
Sula Milani ◽  
Matteo Alvaro ◽  
Fabrizio Nestola
Keyword(s):  
High Pressure ◽  
Single Crystal ◽  
High Pressures ◽  
Dominant Factor ◽  
Good Precision ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Experimental Protocols ◽  
Diamond Anvil

AbstractWe describe the experimental protocols necessary to measure the crystal structures of minerals trapped within diamonds by single-crystal X-ray diffraction to the same quality as obtained from minerals studied at ambient conditions. The results show that corrections for X-ray absorption in complex cases can be made with good precision. Comparison of the refined structure of a single-crystal olivine inclusion inside a diamond with the structure of a similar olivine held in a high-pressure diamond-anvil cell shows that data resolution, not the correction for absorption effects, is the dominant factor in influencing the quality of structures determined at high pressures by single-crystal X-ray diffraction.

scholarly journals Experimental Issues in In-Situ Synchrotron X-Ray Diffraction at High Pressure and Temperature by Using a Laser-Heated Diamond-Anvil Cell

1997 ◽  
Vol 499 ◽  
Author(s):  
C. S. Yoo ◽  
H. Cynn ◽  
A. Campbell ◽  
J.-Z. Hu
Keyword(s):  
Diamond Anvil Cell ◽  
High Pressures ◽  
Thermal Gradients ◽  
X Ray Diffraction ◽  
High Pressure And Temperature ◽  
X Ray ◽  
Diamond Anvil ◽  
Integrated Technique ◽  
Laser Heated

ABSTRACTAn integrated technique of diamond-anvil cell, laser-heating and synchrotron x-ray diffraction technologies is capable of structural investigation of condensed matter in an extended region of high pressures and temperatures above 100 GPa and 3000 K. The feasibility of this technique to obtain reliable data, however, strongly depends on several experimental issues, including optical and x-ray setups, thermal gradients, pressure homogeneity, preferred orientation, and chemical reaction. In this paper, we discuss about these experimental issues together with future perspectives of this technique for obtaining accurate data.

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