scholarly journals High pressure polymorphism of LiBH4 and of NaBH4

RSC Advances ◽  
2021 ◽  
Vol 11 (41) ◽  
pp. 25274-25283
Author(s):  
Adrien Marizy ◽  
Grégory Geneste ◽  
Gaston Garbarino ◽  
Paul Loubeyre
Keyword(s):  
Phase Diagram ◽  
Density Functional Theory ◽  
High Pressure ◽  
Density Functional ◽  
Diamond Anvil Cell ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Diamond Anvil

Diamond anvil cell experiments are used along with density functional theory calculations to extend the phase diagram of LiBH4 & NaBH4 and explore new NaBH4(H2)x compounds at Mbar pressures.

A high-pressure study of HfC and nano-crystalline TiC by X-ray diffraction and density functional theory calculations

2020 ◽  
Vol 34 (34) ◽  
pp. 2050393
Author(s):  
Lun Xiong ◽  
Bin Li ◽  
Bi Liang ◽  
Jinxia Zhu ◽  
Hong Yi ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Bulk Modulus ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Nano Crystalline

The equation of state (EOS) of HfC and nanosized TiC at high pressure has been studied by means of synchrotron radiation X-ray diffraction (XRD) in a diamond anvil cell (DAC) at ambient temperature, and density functional theory (DFT) calculations. XRD analysis showed that the cubic structure of HfC and nanosized TiC maintained to the maximum pressures. The XRD data yield a bulk modulus [Formula: see text] GPa with [Formula: see text] of HfC. In addition, the bulk modulus of nanosized TiC derived from XRD data is [Formula: see text] GPa with [Formula: see text].

scholarly journals Novel superconducting structures of BH2 under high pressure

2019 ◽  
Vol 21 (10) ◽  
pp. 5466-5473 ◽  
Author(s):  
Wen-Hua Yang ◽  
Wen-Cai Lu ◽  
Shan-Dong Li ◽  
Xu-Yan Xue ◽  
Qing-Jun Zang ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Density Functional Theory ◽  
High Pressure ◽  
Crystal Structures ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Genetic Algorithm Method

The high-pressure crystal structures and superconductivity of BH2 were studied using the genetic algorithm method combined with first-principles density functional theory calculations.

Pressure-induced chemical decomposition of copper orthovanadate (α-Cu3V2O8)

2021 ◽  
Author(s):  
Daniel Diaz-Anichtchenko ◽  
Robin Turnbull ◽  
Enrico Bandiello ◽  
Simone Anzellini ◽  
Srungarpu N. Achary ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Theoretical Density ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Chemical Decomposition ◽  
X Ray ◽  
Pressure Stability

The high pressure stability of α-Cu3V2O8 has been investigated via complementary high pressure synchrotron X-ray diffraction experiments and theoretical density functional theory calculations. The results of both experiment and theory...

scholarly journals Origin of enhanced chemical precompression in cerium hydride $$\hbox {CeH}_{{9}}$$

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hyunsoo Jeon ◽  
Chongze Wang ◽  
Seho Yi ◽  
Jun-Hyung Cho
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Rare Earth ◽  
Rare Earth Metal ◽  
Density Functional ◽  
Metal Hydrides ◽  
Earth Metal ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Valence States

Abstract The rare-earth metal hydrides with clathrate structures have been highly attractive because of their promising high-$$T_{\rm{c}}$$ T c superconductivity at high pressure. Recently, cerium hydride $$\hbox {CeH}_9$$ CeH 9 composed of Ce-encapsulated clathrate H cages was synthesized at much lower pressures of 80–100 GPa, compared to other experimentally synthesized rare-earth hydrides such as $$\hbox {LaH}_{{10}}$$ LaH 10 and $$\hbox {YH}_6$$ YH 6 . Based on density-functional theory calculations, we find that the Ce 5p semicore and 4f/5d valence states strongly hybridize with the H 1s state, while a transfer of electrons occurs from Ce to H atoms. Further, we reveal that the delocalized nature of Ce 4f electrons plays an important role in the chemical precompression of clathrate H cages. Our findings not only suggest that the bonding nature between the Ce atoms and H cages is characterized as a mixture of ionic and covalent, but also have important implications for understanding the origin of enhanced chemical precompression that results in the lower pressures required for the synthesis of $$\hbox {CeH}_9$$ CeH 9 .

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