Towards a Mechanism Underlying the Stability of the Tetragonal CuO Phase: Comparison with NiO and CoO by Hybrid Density Functional Calculation

2014 ◽  
Vol 31 (2) ◽  
pp. 027402 ◽  
Author(s):  
Fang-Fang Wang ◽  
Peng-Yue Wei ◽  
Xue-Yong Ding ◽  
Xian-Ran Xing ◽  
Xing-Qiu Chen
Keyword(s):  
Density Functional ◽  
Density Functional Calculation ◽  
The Stability ◽  
Hybrid Density Functional

Computational Study of Tetrahedral Fullerenes Containing Fused Pentagon-Triples

2021 ◽  
Vol 21 (4) ◽  
pp. 2419-2426
Author(s):  
Csaba L. Nagy ◽  
Katalin Nagy
Keyword(s):  
Density Functional ◽  
Computational Study ◽  
Chemical Shifts ◽  
Point Group ◽  
Functional Theory ◽  
Global Strain ◽  
The Stability ◽  
Global And Local ◽  
Hybrid Density Functional ◽  
Electronic And Structural Properties

Fullerenes that violate the isolated pentagon rule are too reactive and were obtained only as endoor exohedral derivatives. Density functional theory using the B3LYP hybrid density functional was applied to investigate the electronic and structural properties of the ten smallest tetrahedral (Td or T point group) fullerenes containing four directly fused pentagon-triples. The influence of nitrogen doping and exohedral hydrogenation of the four reactive sites was also analyzed. Nucleus independent chemical shifts values computed using B3LYP/6-31G(d) are used as global and local aromaticity probe. The global strain energy is evaluated in terms of the pyramidalization (POAV) angle. The results show that the stability increases with the elimination of the energetically unfavorable strain.

scholarly journals Thermodynamic stability of stoichiometric LaFeO3 and BiFeO3: a hybrid DFT study

2017 ◽  
Vol 19 (5) ◽  
pp. 3738-3755 ◽  
Author(s):  
Eugene Heifets ◽  
Eugene A. Kotomin ◽  
Alexander A. Bagaturyants ◽  
Joachim Maier
Keyword(s):  
Phase Diagrams ◽  
Thermodynamic Stability ◽  
Environmental Conditions ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Oxygen Molecule ◽  
Binary Oxides ◽  
Total Energies ◽  
The Stability ◽  
Hybrid Density Functional

Environmental conditions for the stability of LaFeO3 and BiFeO3 perovskites were assessed using the phase diagrams derived from the results of hybrid density functional calculations of the total energies of these perovskites, related binary oxides and the oxygen molecule.

Influence of defect pairs in Ga-based ordered defect compounds: a hybrid density functional study

2020 ◽  
Vol 98 (8) ◽  
pp. 770-777
Author(s):  
Sudhir Kumar ◽  
Suman Joshi ◽  
Durgesh Kumar Sharma ◽  
Sushil Auluck
Keyword(s):  
Band Gap ◽  
Energy Band ◽  
Density Functional ◽  
Functional Study ◽  
Energy Band Gap ◽  
Functional Theory ◽  
Lattice Constants ◽  
Donor Acceptor ◽  
The Stability ◽  
Hybrid Density Functional

In the present paper, density functional theory (DFT) based calculations have been performed to predict the stability, electronic, and optical properties of Ga-rich ordered defect compounds (ODCs). The calculated lattice constants, bulk modulus, their pressure derivatives, and optical constants show good agreement with available experimental data. The hybrid exchange correlations functional have been considered to calculate ground state total energy and energy band gap of the material. The calculated formation energy of ODCs comes smaller than pure CuGaSe2 (CGS). Our calculated optical absorption coefficients indicate that the energy band gap of ODCs can be tuned by changing the number of donor–acceptor defect pairs ([Formula: see text]). The band offset has been calculated to understand the reason of band gap alteration while the number of defect pair changes. Our results may be helpful for other experiments to further improve the performance of ODCs.

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