A complete ab initio thermodynamic and kinetic catalogue of the defect chemistry of hematite α-Fe2O3, its cation diffusion, and sample donor dopants

Author(s):  
Shehab Shousha ◽  
Sarah Khalil ◽  
Mostafa Youssef

This paper studies comprehensively the defect chemistry and cation diffusion in α-Fe2O3. Defect formation energies and migration barriers are calculated using density functional theory with a theoretically calibrated Hubbard U...

2008 ◽  
Vol 1122 ◽  
Author(s):  
Byeong-Eon Lee ◽  
Dae-Hee Kim ◽  
Yeong-Cheol Kim

AbstractWe studied oxygen migration in calcia-stabilized cubic zirconia (CSZ) using density functional theory. A Ca atom was substituted for a Zr atom in a 2×2×2 ZrO2 cubic supercell, and an oxygen vacancy was produced to satisfy the charge neutrality condition. We found that the formation energies of an oxygen vacancy, as a function of its location with respect to the Ca atom, were varied. The relative formation energies of the oxygen vacancies located at the first-, second-, third-, and fourth-nearest-neighbors were 0.0, −0.07, 0.19, and 0.19 eV, respectively. Therefore, the oxygen vacancy located at the second-nearest-neighbor site of the Ca atom was the most favorable, the oxygen vacancy located at the first-nearest-neighbor site was the second most favorable, and the oxygen vacancies at the third- and fourth-nearest-neighbor sites were the least favorable. We also calculated the energy barriers for the oxygen vacancy migration between oxygen sites. The energy barriers between the first and the second nearest sites, the second and third nearest sites, and the third and fourth nearest sites were 0.11, 0.46, and 0.23 eV, respectively. Therefore, the oxygen vacancies favored the first- and second-nearest-neighbor oxygen sites when they drifted under an electric field.


RSC Advances ◽  
2016 ◽  
Vol 6 (38) ◽  
pp. 31968-31975 ◽  
Author(s):  
Shuai Zhao ◽  
Liguo Gao ◽  
Chunfeng Lan ◽  
Shyam S. Pandey ◽  
Shuzi Hayase ◽  
...  

In this work, we present a detailed first-principles investigation on the stoichiometric and oxygen-deficient structures of double perovskites, Sr2BMoO6 (B = Mg, Co and Ni), using the density functional theory (DFT) method.


INEOS OPEN ◽  
2021 ◽  
Vol 4 ◽  
Author(s):  
Yu. A. Borisov ◽  
◽  
S. S. Kiselev ◽  

The interaction of cucurbiturils (Q6, Q7, and Q8) with Ca and Ba chlorides and iodides are studied for the first time by density functional theory. The thermodynamic parameters for the formation of host–guest complexes are calculated. The structures of complexes of Q6 and Q7 with one and two guest molecules are established. The energy parameters for the transfer of Be2+ and Ba2+ cations from an aqueous solution into the cavity of Q7 containing n water molecules are defined. The dependences of the formation energies for complexes Q7WnBe2+ and Q7WnBa2+ on the number of water molecules are shown to be parabolic, with the energy minima at n = 5 and n = 6, respectively. It is found that Q7 can form in an aqueous solution supramolecular complexes with protonated histamine (HA) and neutral histamine in the presence of Ca2+ ions.


2015 ◽  
Vol 17 (48) ◽  
pp. 32547-32555 ◽  
Author(s):  
Ziheng Lu ◽  
Chi Chen ◽  
Zarah Medina Baiyee ◽  
Xin Chen ◽  
Chunming Niu ◽  
...  

The defect chemistry and the associated lithium transport in Li3OCl anti-perovskite superionic conductors are studied using molecular dynamics and density functional theory.


2020 ◽  
Vol 52 (8) ◽  
pp. 493-498
Author(s):  
Huiling Jia ◽  
Hao Chen ◽  
Jinxiu Wu ◽  
Xin Tan ◽  
Mei Li ◽  
...  

2019 ◽  
Vol 21 (30) ◽  
pp. 16818-16829 ◽  
Author(s):  
P. S. Ghosh ◽  
A. Arya

Formation energies of PuO2, α-Pu2O3 and sub-oxides PuO2−x (0.0 < x < 0.5) are determined using density functional theory employing generalised gradient approximation corrected with an effective Hubbard parameter.


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