scholarly journals Reconciling the valence state with magnetism in mixed-valent polyoxometalates: the case of a {VO2F2@V22O54} cluster

2017 ◽  
Vol 19 (44) ◽  
pp. 29767-29771 ◽  
Author(s):  
Piotr Kozłowski ◽  
Almudena Notario-Estévez ◽  
Coen de Graaf ◽  
Xavier López ◽  
Kirill Yu. Monakhov

The interplay between density functional theory and effective Hamiltonian calculations is determinative for understanding of the magnetochemistry of a polyoxovanadate(iv,v) structure with complex electronic and magnetic effects.

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 197
Author(s):  
Si-Mei Fu ◽  
Yue Zhao ◽  
Jiang-Tao Liu ◽  
Wen-Sheng Liang ◽  
Gang-Sen Li ◽  
...  

Benzoic acid (C6H5COOH) is selected as coal-based model compound with Co compounds (Co3O4, CoO and Co) as the catalysts, and the influence of the valence state change of the catalyst for pyrolysis process is investigated using density functional theory (DFT). DFT results shows that the highest energy barrier of C6H5COOH pyrolysis is in the following order: Ea(CoO) <Ea(Co3O4) <Ea(no catalyst) <Ea(Co). In general, Co3O4 catalyst accelerates C6H5COOH pyrolysis. Then, the catalytic activity further increases when Co3O4 is reduced to CoO. Finally, Co shows no activity for C6H5COOH pyrolysis due to the reduction of CoO to metallic Co.


2019 ◽  
Vol 478 ◽  
pp. 313-318 ◽  
Author(s):  
Yue Zhao ◽  
Jiang-Tao Liu ◽  
Wen-Sheng Liang ◽  
Wei Huang ◽  
Zhi-Jun Zuo

2020 ◽  
Author(s):  
Xindong Wang

We propose a general variational fermionic many-body wavefunction that generates an effective Hamiltonian in quadratic form which can then be exactly solved. The theory can be constructed within density functional theory framework and a self-consistent scheme is proposed for solving the exact density functional theory. We apply the theory to structurally disordered system and an symmetric and asymmetric Hubbard dimer and corresponding lattice models and the the single fermion excitation spectra show a persistent gap due to the fermionic entanglement induced pairing condensate. For disordered system, density of state at the edge of the gap diverges in the thermodynamic limit, suggesting a topologically ordered phase and a sharp resonance is predicted as the gap is not dependent on the temperature of the system. For the symmetric Hubbard model, the gap for both half filling and doped case suggests quantum phase transition between the AFM and SC is a continuous phase transition.


2019 ◽  
Vol 21 (44) ◽  
pp. 24478-24488 ◽  
Author(s):  
Martin Gleditzsch ◽  
Marc Jäger ◽  
Lukáš F. Pašteka ◽  
Armin Shayeghi ◽  
Rolf Schäfer

In depth analysis of doping effects on the geometric and electronic structure of tin clusters via electric beam deflection, numerical trajectory simulations and density functional theory.


2000 ◽  
Vol 98 (20) ◽  
pp. 1639-1658 ◽  
Author(s):  
Yuan He, Jurgen Grafenstein, Elfi Kraka,

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