scholarly journals Theoretical design of a technetium-like alloy and its catalytic properties

2019 ◽  
Vol 10 (21) ◽  
pp. 5461-5469
Author(s):  
Wei Xie ◽  
Michihisa Koyama

Based on the concept of density of states (DOS) engineering, we theoretically designed a pseudo-Tc material (Mo–Ru alloy) and investigated its electronic structure, phase stability and catalytic activity by using density functional theory.

2009 ◽  
Vol 23 (19) ◽  
pp. 2339-2352 ◽  
Author(s):  
LI BIN SHI ◽  
SHUANG CHENG ◽  
RONG BING LI ◽  
LI KANG ◽  
JIAN WEI JIN ◽  
...  

Density of states and band structure of wurtzite ZnO are calculated by the CASTEP program based on density functional theory and plane-wave pseudopotential method. The calculations are carried out in axial and unaxial strains, respectively. The results of density of states in different strains show that the bottom of the conduction band is always dominated by Zn 4s, and the top of valence band is always dominated by O 2p. The variation of the band gap calculated from band structure is also discussed. In addition, p-d repulsion is used in investigating the variation of the top of the valence band in different strains and the results can be verified by electron density difference.


2019 ◽  
Vol 11 (02) ◽  
pp. 2030001 ◽  
Author(s):  
Dung Nguyen-Trong ◽  
Cuong Nguyen-Chinh ◽  
Van Duong-Quoc

This paper studies the effect of GGA-PBE, GGA-PBEsol, GGA-PW91, GGA-VWN-BP, LDA-PWC, LDA-VWN parameterized exchange–correlation functionals and Cu impurity concentration on the lattice and electronic properties of bulk AuCu by the Density Functional Theory (DFT). The lattice properties are determined by the lattice constant, the unit cell volume and the total energy on unit cell. The electronic properties are determined by the band gap, the Partial Density of States (PDOS) and the total Density of States (DOS) of materials. The obtained results showed the effect of the interaction potential and the Cu impurity concentration on the lattice structure and the electronic structure of bulk AuCu.


2015 ◽  
Vol 17 (15) ◽  
pp. 9706-9715 ◽  
Author(s):  
J. Sirijaraensre ◽  
J. Limtrakul

By means of the density functional theory calculations, enhanced catalytic activity of Au4 cluster for the partial oxidation of methane with the N2O oxidant is observed when the cluster is deposited on top of the Pd/graphene.


2015 ◽  
Vol 29 (15) ◽  
pp. 1550094 ◽  
Author(s):  
Arvids Stashans ◽  
Jairo Escobar

Our present work is based on the density functional theory (DFT) studies of TiO 2 crystals doped with V impurities. Both rutile and anatase structures have been considered within the present research and different defect concentrations have been used as well. Our calculations reveal equilibrium geometry of the system showing atomic rearrangement around the point defect being mainly inward with respect to the impurity. Magnetism and electronic structure based on the density of states (DOS) patterns for both rutile and anatase crystals have been obtained and discussed in detail. It is shown that local magnetic moments arise mainly from the 3d states of the impurity atom with some admixture of 2p states from the vanadium-nearest O atoms.


2018 ◽  
Vol 20 (27) ◽  
pp. 18623-18629 ◽  
Author(s):  
T. Mukherjee ◽  
Sumona Sinha ◽  
M. Mukherjee

X-ray absorption spectra (XAS), the density of states (DOS) and the electron density distribution of the HOMO and LUMO for flat and twisted rubrene molecules have been calculated using density functional theory (DFT).


2017 ◽  
Vol 7 (3) ◽  
pp. 687-692 ◽  
Author(s):  
Showkat H. Mir ◽  
Sudip Chakraborty ◽  
John Wärnå ◽  
Som Narayan ◽  
Prakash C. Jha ◽  
...  

In this study, we investigated the catalytic activity of ultrathin PtS2 and WS2 nanostructures for the hydrogen evolution reaction by electronic structure calculations based on the spin-polarised density functional theory.


2015 ◽  
Vol 17 (39) ◽  
pp. 26140-26148 ◽  
Author(s):  
Linn Leppert ◽  
Rhett Kempe ◽  
Stephan Kümmel

We investigate the electronic structure of nickel–palladium systems with first-principles density functional theory (DFT).


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Farshad Nejadsattari ◽  
Zbigniew M. Stadnik

AbstractUsing density-functional theory, we investigate the electronic, magnetic, and hyperfine-interaction properties of the 112-type iron-pnictide compound $${\hbox {EuFeAs}}_2$$ EuFeAs 2 , which is isostructural to the high-temperature iron-based superconductor $${\hbox {Ca}}_{1-x}{\hbox {La}}_x{\hbox {FeAs}}_2$$ Ca 1 - x La x FeAs 2 . We show that the band structure of $${\hbox {EuFeAs}}_2$$ EuFeAs 2 is similar to that of the 112-type compounds’ family, with hole-like and electron-like bands at the Brillouin-zone center and corners, respectively. We demonstrate that the bands near the Fermi level originate mainly from the Fe atoms. The presence of a mixture of ionic and covalent bonding is predicted from the charge-density and atom-resolved density-of-states calculations. There is good agreement between the calculated hyperfine-interaction parameters with those obtained from the $$^{57}$$ 57 Fe and $$^{151}$$ 151 Eu Mössbauer measurements. The spatial distribution of atoms in $${\hbox {EuFeAs}}_2$$ EuFeAs 2 leads to an in-plane 2D magnetism. Moreover, ab-initio calculations predict the compound’s magnetic moment and the magnetic moments of each constituent atom. Also, the density of states profile provides insight into the relative magnitude of these moments. Electronic structure calculations and Fermi surface topology reveal various physical and chemical properties of $${\hbox {EuFeAs}}_2$$ EuFeAs 2 . Valence electron density maps indicate the co-existence of a wide range of chemical bonds in this system, and based on structural properties, the transport characteristics are deduced and discussed. A thorough analysis of the atomic structure of $${\hbox {EuFeAs}}_2$$ EuFeAs 2 and its role in the bond formation is presented.


2016 ◽  
Vol 846 ◽  
pp. 561-566 ◽  
Author(s):  
Choon Min Cheong ◽  
Md Mahmudur Rahman ◽  
Abdul Halim Shaari ◽  
Soo Kien Chen

In this work, we analyze the electronic structure and charge distribution of the YBCO family compounds Y-123 and Y-124 bulk using the density functional theory. The band structures and the density of states of the compounds are shown. The charge transfers between the atoms in the two compounds are compared and discussed in detail. The lattice parameters obtained by Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm are compared with the experimental parameters. The critical differences of the charge distribution for these two compounds are discussed.


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