scholarly journals Fluorine chemistry at extreme conditions: possible synthesis of $HgF_4$

2019 ◽  
Vol 11 ◽  
pp. 110001 ◽  
Author(s):  
Michael G. Pravica ◽  
Sarah Schyck ◽  
Blake Harris ◽  
Petrika Cifligu ◽  
Eunja Kim ◽  
...  
Keyword(s):  
Pressure Range ◽  
Diamond Anvil Cell ◽  
Theoretical Calculations ◽  
Far Infrared ◽  
X Rays ◽  
Creative Commons ◽  
Pressure Cycling ◽  
Spectral Changes ◽  
Sample Chamber ◽  
Diamond Anvil

By irradiating a pressurized mixture of a fluorine-bearing compound ($XeF_2$) and $HgF_2$ with synchrotron hard x-rays (>7 keV) inside a diamond anvil cell, we have observed dramatic changes in the far-infrared spectrum within the 30-35 GPa pressure range which suggest that we may have formed $HgF_4$ in the following way: $XeF_2 \xrightarrow{hv} Xe + F_2$ (photochemically) and $HgF_2 + F_2 \rightarrow HgF_4$ (30 GPa < P < 35 GPa). This lends credence to recent theoretical calculations by Botana et al. that suggest that Hg may behave as a transition metal at high pressure in an environment with an excess of molecular fluorine. The spectral changes were observed to be reversible during pressure cycling above and below the above mentioned pressure range until a certain point when we suspect that molecular fluorine diffused out of the sample at lower pressure. Upon pressure release, $HgF_2$ and trace $XeF_2$ were observed to be remaining in the sample chamber suggesting that much of the $Xe$ and $F_2$ diffused and leaked out from the sample chamber.   Received: 29 October 2018,  Accepted: 18 January 2019; Edited by: A. Goñi, A. Cantarero, J. S. Reparaz; DOI: http://dx.doi.org/10.4279/PIP.110001 Cite as: M Pravica, S Schyck, B Harris, P Cifligu, E Kim, B Billinghurst, Papers in Physics 11, 110001 (2019). This paper, by M Pravica, S Schyck, B Harris, P Cifligu, E Kim, B Billinghurst, is licensed under the Creative Commons Attribution License 4.0.  

Diamond-Anvil Cell Observations of a New Methane Hydrate Phase in the 100-MPa Pressure Range

2001 ◽  
Vol 105 (19) ◽  
pp. 4664-4668 ◽  
Author(s):  
I-Ming Chou ◽  
Anurag Sharma ◽  
Robert C. Burruss ◽  
Russell J. Hemley ◽  
Alexander F. Goncharov ◽  
...  
Keyword(s):  
Methane Hydrate ◽  
Pressure Range ◽  
Diamond Anvil Cell ◽  
Hydrate Phase ◽  
Diamond Anvil

scholarly journals Homogenization Experiments of Crystal-Rich Inclusions in Spodumene from Jiajika Lithium Deposit, China, under Elevated External Pressures in a Hydrothermal Diamond-Anvil Cell

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Jiankang Li ◽  
I-Ming Chou
Keyword(s):  
Diamond Anvil Cell ◽  
Aqueous Fluid ◽  
Formation Mechanisms ◽  
External Pressures ◽  
Sample Chamber ◽  
New Type ◽  
Diamond Anvil ◽  
In Situ Observations ◽  
Total Dissolution

Extensive studies of the crystal-rich inclusions (CIs) hosted in minerals in pegmatite have resulted in substantially different models for the formation mechanism of the pegmatite. In order to evaluate these previously proposed formation mechanisms, the total homogenization processes of CIs hosted in spodumene from the Jiajika pegmatite deposit in Sichuan, China, were observed in situ under external H2O pressures in a new type of hydrothermal diamond-anvil cell (HDAC). The CIs in a spodumene chip were loaded in the sample chamber of HDAC with water, such that the CIs were under preset external H2O pressures during heating to avoid possible decrepitation. Our in situ observations showed that the crystals within the CIs were dissolved in carbonic-rich aqueous fluid during heating and that cristobalite was usually the first mineral being dissolved, followed by zabuyelite and silicate minerals until their total dissolution at temperatures between 500 and 720°C. These observations indicated that the minerals within the CIs were daughter minerals crystallized from an entrapped carbonate- and silica-rich aqueous solution and therefore provided useful information for evaluating the formation models of granitic pegmatites.

THE ENHANCED SUPERCONDUCTIVITY OF Cu-1234 UNDER HIGH PRESSURE

2005 ◽  
Vol 19 (01n03) ◽  
pp. 335-337 ◽  
Author(s):  
C. Q. JIN ◽  
X. M. QIN ◽  
K. SHIMIZU ◽  
M. NISHIYAMA ◽  
T. NAMIKI ◽  
...  
Keyword(s):  
Pressure Range ◽  
Diamond Anvil Cell ◽  
Pressure Effect ◽  
Positive Pressure ◽  
Superconducting Transition ◽  
Wide Pressure Range ◽  
Diamond Anvil ◽  
The One ◽  
Enhanced Superconductivity ◽  
Wide Pressure

The evolution of superconducting transition of CuBa 2 Ca 3 Cu 4 O 10+δ (i.e. Cu -1234) superconductor has been studied by using diamond anvil cell technique. The Tc of Cu -1234 can be enhanced continuously from ambient reaching to 123 K at 15 GPa. This seems the one more system besides Hg -12( n -1) n which demonstrate the positive pressure effect on Tc over a wide pressure range above 10 GPa.

PRESSURE-INDUCED SUPERCONDUCTIVITY IN SYMPLE METALS

2005 ◽  
Vol 19 (01n03) ◽  
pp. 259-261
Author(s):  
KATSUYA SHIMIZU
Keyword(s):  
Pressure Range ◽  
Diamond Anvil Cell ◽  
Molecular Crystals ◽  
Dilution Refrigerator ◽  
Extreme Condition ◽  
Organic Molecular Crystals ◽  
Ultra High Pressure ◽  
Experimental Apparatus ◽  
Diamond Anvil ◽  
Very Low Temperature

Experimental results in search for pressure-induced superconductivity are reviewed. Typical examples are simple inorganic and organic molecular crystals, magnetic metals, and elements. We have developed complex extreme condition of very low temperature down to 30 mK and ultra high pressure exceeding 200 GPa by assembling compact diamond-anvil cell (DAC) on a powerful 3 He /4 He dilution refrigerator. Using the newly developed apparatus and techniques, we have studied superconductivity in various materials in various pressure range. In this paper, we will shortly review our newly developed experimental apparatus and techniques and discuss about examples of pressure-induced superconductivity in simple metals.

scholarly journals Diamond anvil cell behavior up to 4 Mbar

2018 ◽  
Vol 115 (8) ◽  
pp. 1713-1717 ◽  
Author(s):  
Bing Li ◽  
Cheng Ji ◽  
Wenge Yang ◽  
Junyue Wang ◽  
Ke Yang ◽  
...  
Keyword(s):  
Pressure Range ◽  
Diamond Anvil Cell ◽  
Static Pressure ◽  
Thickness Variation ◽  
Cell Behavior ◽  
Pressure Loading ◽  
X Ray ◽  
Pressure Limit ◽  
Diamond Anvils ◽  
Diamond Anvil

The diamond anvil cell (DAC) is considered one of the dominant devices to generate ultrahigh static pressure. The development of the DAC technique has enabled researchers to explore rich high-pressure science in the multimegabar pressure range. Here, we investigated the behavior of the DAC up to 400 GPa, which is the accepted pressure limit of a conventional DAC. By using a submicrometer synchrotron X-ray beam, double cuppings of the beveled diamond anvils were observed experimentally. Details of pressure loading, distribution, gasket-thickness variation, and diamond anvil deformation were studied to understand the generation of ultrahigh pressures, which may improve the conventional DAC techniques.

Improved calibtration curve for the Sm2+:BaFCl pressure sensor

1993 ◽  
Vol 26 (6) ◽  
pp. 843-845 ◽  
Author(s):  
P. Comodi ◽  
P. F. Zanazzi
Keyword(s):  
Equation Of State ◽  
Pressure Sensor ◽  
Electronic Transition ◽  
Pressure Range ◽  
Diamond Anvil Cell ◽  
Moderate Pressure ◽  
Pressure Measurements ◽  
Luminescence Line ◽  
Diamond Anvil ◽  
Estimated Error

The pressure sensor proposed by Shen, Gregorian & Holzapfel [High Press. Res. (1991), 7, 73–75], based on the pressure-dependent shift of the luminescence line due to the 5 D 0−7 F 0 electronic transition of Sm2+ in a matrix of BaFCl, has been tested in a diamond-anvil cell and calibrated against the R 1−R 2 doublet shift of ruby and the known NaCl equation of state, in the pressure range between 0.0001 and 4.3 GPa. The parabolic dependence of the shift from the pressure can be approximated by the equation Δ(nm) = 1.46P − 0.047P 2, where the shift, Δ, is in nm and the pressure, P, in GPa. The estimated error in the pressure measurements is 5%. The Sm2+: BaFCl luminescence sensor can be advantageously used in the low to moderate pressure range (0.0001–5 GPa or more).

Synthesis and characterization of nitrides of iridium and palladium

2008 ◽  
Vol 23 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Jonathan C. Crowhurst ◽  
Alexander F. Goncharov ◽  
B. Sadigh ◽  
J.M. Zaug ◽  
D. Aberg ◽  
...  
Keyword(s):  
First Principles ◽  
Diamond Anvil Cell ◽  
Theoretical Calculations ◽  
X Ray ◽  
In Situ Techniques ◽  
Diamond Anvil ◽  
Experimental Findings ◽  
Laser Heated

We describe the synthesis of nitrides of iridium and palladium using the laser-heated diamond anvil cell. We have used the in situ techniques of x-ray powder diffraction and Raman scattering to characterize these compounds and have compared our experimental findings where possible to the results of first-principles theoretical calculations. We suggest that palladium nitride is isostructural with pyrite, while iridium nitride has a monoclinic symmetry and is isostructural with baddeleyite.

High-pressure single-crystal study on AlPO4 with synchrotron radiation

1990 ◽  
Vol 23 (5) ◽  
pp. 397-400 ◽  
Author(s):  
H. Sowa ◽  
K. Reithmayer ◽  
J. Macavei ◽  
W. Rieck ◽  
H. Schulz ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Single Crystal ◽  
Diamond Anvil Cell ◽  
Structural Parameters ◽  
X Rays ◽  
X Ray ◽  
Single Crystal Study ◽  
Diamond Anvil ◽  
Counting Statistics ◽  
Good Agreement

A single-crystal study on AlPO4 was performed at 2.90 (7) GPa with synchrotron radiation using a diamond-anvil cell with a beryllium gasket. For the data collection the radiation wavelength of only 0.54 Å, was chosen to minimize the absorption of X-rays in the pressure cell. The diffracted intensity was high enough to measure even weak reflections with sufficient counting statistics. The refined structural parameters are in good agreement with those determined from data collected with a conventional X-ray tube.

A Supported Ultrathin Window for Improved Performance in Gas Flow Proportional Counters

1995 ◽  
Vol 39 ◽  
pp. 881-884
Author(s):  
Andrew J. Nelson ◽  
David Tingey ◽  
Takashi Shoji ◽  
Kazuaki Shimizu
Keyword(s):  
Gas Flow ◽  
Theoretical Calculations ◽  
Light Element ◽  
X Rays ◽  
X Ray ◽  
Pressure Cycling ◽  
Trade Offs ◽  
Proportional Counters ◽  
Improved Performance ◽  
Additional Support

Polypropylene windows stretched to 1-1.5 μm in thickness have been traditionally used for soft x-ray detection on gas flow proportional counters. Theoretical calculations show that significant transmission Improvement could result from a thinner window. The trade-offs to ultimate transmission have traditionally been reliability and durability. A 0.3 um window has been fabricated to show significant improvement for light element transmission, A supporting grid was used to back the film and provide additional support and durability to allow for pressure cycling during venting of the spectrometer chamber. Significant transmission improvements were observed for ultra soft x rays in the energy range below 1 KeV.

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