Elucidation of hydrolysis reaction mechanism of tungsten hexafluoride (WF6) using first-principles calculations

2019 ◽  
Vol 70 ◽  
pp. 99-102
Author(s):  
Hyunwook Jung ◽  
Jeemin Hwang ◽  
Hoje Chun ◽  
Byungchan Han
Keyword(s):  
Reaction Mechanism ◽  
First Principles ◽  
Hydrolysis Reaction ◽  
First Principles Calculations ◽  
Tungsten Hexafluoride

Reaction mechanism of metal and pyrite under HPHT conditions and improvement of the properties

2022 ◽  
Author(s):  
Yao Wang ◽  
Dan Xu ◽  
Shan Gao ◽  
Qi Chen ◽  
Dayi Zhou ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Pressure ◽  
Reaction Mechanism ◽  
First Principles ◽  
Room Temperature ◽  
First Principles Calculations ◽  
Mine Wastewater ◽  
Al Addition ◽  
Thermal Stability Of ◽  
Pyrite Tailings

Abstract Pyrite tailings are the main cause of acid mine wastewater. An idea was put forward to more effectively use pyrite, and it was modified by exploiting the reducibility of metal represented by Al under high-pressure and high-temperature (HPHT) conditions. Upon increasing the Al addition, the conductivity of pyrite were effectively improved, which is nearly 734-times higher than that of unmodified pyrite at room temperature. First-principles calculations were used to determine the influence of a high pressure on the pyrite lattice. The high pressure increased the thermal stability of pyrite, reduced pyrite to high-conductivity Fe7S8 (pyrrhotite) by Al, and prevented the formation of iron. Through hardness and density tests the influence of Al addition on the hardness and toughness of samples was explored. Finally the possibility of using other metal-reducing agents to improve the properties of pyrite was discussed.

Electronic Structure and X-ray Absorption Spectra of Rutile TiO2 Using First-Principles Calculations

2014 ◽  
Vol 52 (12) ◽  
pp. 1025-1029
Author(s):  
Min-Wook Oh ◽  
Tae-Gu Kang ◽  
Byungki Ryu ◽  
Ji Eun Lee ◽  
Sung-Jae Joo ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Absorption Spectra ◽  
First Principles ◽  
First Principles Calculations ◽  
Rutile Tio2 ◽  
X Ray ◽  
X Ray Absorption

To Bend or Not to Bend, the Dilemma of Multiple Bonds

2019 ◽  
Author(s):  
Michele Pizzocchero ◽  
Matteo Bonfanti ◽  
Rocco Martinazzo
Keyword(s):  
First Principles ◽  
2D Materials ◽  
Main Group ◽  
First Principles Calculations ◽  
Group 14 ◽  
Multiple Bonds ◽  
Main Group Elements ◽  
Structural Distortions

The manuscript addresses the issue of the structural distortions occurring at multiple bonds between high main group elements, focusing on group 14. These distortions are known as trans-bending in silenes, disilenes and higher group analogues, and buckling in 2D materials likes silicene and germanene. A simple but correlated \sigma + \pi model is developed and validated with first-principles calculations, and used to explain the different behaviour of second- and higher- row elements.

Thermodynamic Stability of Hexagonal and Rhombohedral Bn at Cvd Conditions from Van der Waals Corrected First Principles Calculations

2019 ◽  
Author(s):  
Henrik Pedersen ◽  
Björn Alling ◽  
Hans Högberg ◽  
Annop Ektarawong
Keyword(s):  
Thin Films ◽  
Thermodynamic Stability ◽  
First Principles ◽  
Thermal Equilibrium ◽  
Density Functional ◽  
Van Der Waals ◽  
Chemical Vapor ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Stability

Thin films of boron nitride (BN), particularly the sp<sup>2</sup>-hybridized polytypes hexagonal BN (h-BN) and rhombohedral BN (r-BN) are interesting for several electronic applications given band gaps in the UV. They are typically deposited close to thermal equilibrium by chemical vapor deposition (CVD) at temperatures and pressures in the regions 1400-1800 K and 1000-10000 Pa, respectively. In this letter, we use van der Waals corrected density functional theory and thermodynamic stability calculations to determine the stability of r-BN and compare it to that of h-BN as well as to cubic BN and wurtzitic BN. We find that r-BN is the stable sp<sup>2</sup>-hybridized phase at CVD conditions, while h-BN is metastable. Thus, our calculations suggest that thin films of h-BN must be deposited far from thermal equilibrium.

Combined DFT and kinetic Monte Carlo study of a bridging-spillover mechanism on fluorine-decorating graphene

2020 ◽  
Author(s):  
Jing-hua Guo ◽  
Jin-Xiang Liu ◽  
Hongbo Wang ◽  
Haiying Liu ◽  
Gang Chen
Keyword(s):  
Monte Carlo ◽  
First Principles ◽  
Kinetic Monte Carlo ◽  
Monte Carlo Study ◽  
First Principles Calculations ◽  
Graphene Surface

In this work, combining the first-principles calculations with kinetic Monte Carlo (KMC) simulations, we constructed an irregular carbon bridge on the graphene surface and explored the process of H migration...

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