scholarly journals Electronic Structure of Copper Antimony Using Compton Scattering Technique

2018 ◽  
Vol 13 (1) ◽  
pp. 167-173
Author(s):  
Baghdad Science Journal
Keyword(s):  
Electronic Structure ◽  
Dft Calculation ◽  
Function Theory ◽  
Momentum Density ◽  
Density Function Theory ◽  
Ionic Model ◽  
Model Calculations ◽  
Electron Momentum ◽  
Atomic Orbitals ◽  
Scattering Technique

In this paper we present the first ever measured experimental electron momentum density of Cu2Sb at an intermediate resolution (0.6 a.u.) using 59.54 keV 241Am Compton spectrometer. The measurements are compared with the theoretical Compton profiles using density function theory (DFT) within a linear combination of an atomic orbitals (LCAO) method. In DFT calculation, Perdew-Burke-Ernzerhof (PBE) scheme is employed to treat correlation whereas exchange is included by following the Becke scheme. It is seen that various approximations within LCAO-DFT show relatively better agreement with the experimental Compton data. Ionic model calculations for a number of configurations (Cu+x/2)2(Sb-x) (0.0≤x≤2.0) are also performed utilizing free atom profiles, the ionic model suggests transfer of 2.0 electrons per Cu atom from 4s state to 5p state of Sb.

Use of a Lowest Intensity 241Am Compton Spectrometer for the Measurement of Directional Compton Profiles of ZnSe

2006 ◽  
Vol 61 (7-8) ◽  
pp. 364-370 ◽  
Author(s):  
Babu Lal Ahuja ◽  
Narayan Lal Heda
Keyword(s):  
Bond Length ◽  
Theoretical Calculations ◽  
The Other ◽  
Energy Bands ◽  
Electron Momentum ◽  
Atomic Orbitals ◽  
Hartree Fock ◽  
Self Consistent ◽  
Scattering Technique ◽  
Small Disc

In this paper we report on electron momentum densities in ZnSe using Compton scattering technique. For the directional measurements we have employed a newly developed 100 mCi 241Am Compton spectrometer which is based on a small disc source with shortest geometry. For the theoretical calculations we have employed a self-consistent Hartree-Fock linear combination of atomic orbitals (HF-LCAO) approach. It is seen that the anisotropy in the measured Compton profiles is well reproduced by our HF-LCAOcalculation and the other available pseudopotential data. The anisotropy in the Compton profiles is explained in terms of energy bands and bond length. - PACS numbers: 13.60.Fz, 78.70. Ck, 78.70.-g

First Principles Calculation of Geometrical and Electronic Structure of Semiconductor Fe1-xMnxSi2

2011 ◽  
Vol 213 ◽  
pp. 483-486
Author(s):  
Fang Gui ◽  
Shi Yun Zhou ◽  
Wan Jun Yan ◽  
Chun Hong Zhang ◽  
Xiao Tian Guo ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Function Theory ◽  
Density Function Theory ◽  
First Principles Calculation ◽  
First Principle ◽  
Substitutional Doping ◽  
Pseudo Potential ◽  
Mn Concentrations

The electronic structure and optical properties of Fe1-xMnxSi2 have been studied using the first principle plane-wave pseudo-potential based on the density function theory. Substitutional doping is considered with Mn concentrations of x=0.0625, 0.125, 0.1875 and 0.25, respectively. The calculated results show that the volume of β-FeSi2 increase and the band gap increase with increasing of Mn.

Effect of Al, Ti and Cr Doping on Vanadium Dioxide (VO2) Analyzed by Density Function Theory (DFT) Method

2020 ◽  
Vol 20 (3) ◽  
pp. 1651-1659 ◽  
Author(s):  
Hongmei Zhu ◽  
Zhengjie Zhang ◽  
Xuchuan Jiang
Keyword(s):  
Electronic Structure ◽  
Band Gap ◽  
Density Function ◽  
Vanadium Dioxide ◽  
Function Theory ◽  
Dft Method ◽  
Density Function Theory ◽  
Atomic Scale ◽  
Elemental Doping ◽  
Cr Doping

Density function theory (DFT) method was developed and applied for fundamentally understanding the doping effect of various metals (Al, Ti and Cr) on vanadium dioxide (VO2). The substitution doping of Al, Ti and Cr in VO2 could lead to significant changes in electronic structure, band gap and optical property. Different from physical experiments, the DFT method could be utilized for fundamental understandings at an atomic scale. It was found via DFT calculations that: (i) Al doping caused a slightly distorted octahedron in monoclinic VO2(M), and narrowed the band gap of VO2(M) due to the upward shift of the valence band (VB), while Cr doping narrowed the band gap because of the downward shift of the conduction band (CB); (ii) Ti doping slightly widened the band gap of VO2(M); and (iii) the optical reflectivity of VO2(M) decreased after substitution doping low-valent metals (e.g., Al). This study will be beneficial for designing and controlling elemental doping to obtain metal oxide nanocomposites with unique band gap and electronic structure for thermochromic energy saving applications.

Electronic structure and electron momentum density in TiSi

2013 ◽  
Vol 412 ◽  
pp. 106-111 ◽  
Author(s):  
A.M. Ghaleb ◽  
F.M. Mohammad ◽  
Jagrati Sahariya ◽  
Mukesh Sharma ◽  
B.L. Ahuja
Keyword(s):  
Electronic Structure ◽  
Momentum Density ◽  
Electron Momentum ◽  
Electron Momentum Density

scholarly journals Communication—Fe-MOF Exhibits Higher Oxygen Evolution Ability by Electronic Modulation of Sodium Hypochlorite

2021 ◽  
Author(s):  
Guomei Mu ◽  
Yujie Miao ◽  
Mengjiao Wu ◽  
Qiaoyue Xiang ◽  
Dunmin Lin ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Catalytic Activity ◽  
Oxygen Evolution ◽  
Sodium Hypochlorite ◽  
Terephthalic Acid ◽  
Function Theory ◽  
Nickel Foam ◽  
Density Function Theory ◽  
The Third ◽  
Fe Sites

Abstract Development of robust alkaline oxygen evolution reaction electrocatalysts is crucial for the efficiency of water splitting. Herein, Fe-MOF nanocones array on nickel foam are synthesized by introducing sodium hypochlorite, leading to Cl substitution of terephthalic acid in Fe-MOFs (Fe-MOF-Cl/NF). Experimental results show that Fe-MOF-Cl/NF exhibits enhanced OER activity over Fe-MOF/NF, lowering η50 from 292.4 to 222.7 mV. In combination with density function theory calculations, the improved OER performance is attributed to engineering electronic structure of Fe sites which accelerate the third step from *O to *OOH, and promote OER kinetics. Additionally, Fe-MOF-Cl/NF can retain catalytic activity for 100 h.

scholarly journals A strenuous experimental journey searching for spectroscopic evidence of a bridging nickel–iron–hydride in [NiFe] hydrogenase

2015 ◽  
Vol 22 (6) ◽  
pp. 1334-1344 ◽  
Author(s):  
Hongxin Wang ◽  
Yoshitaka Yoda ◽  
Hideaki Ogata ◽  
Yoshihito Tanaka ◽  
Wolfgang Lubitz
Keyword(s):  
Synchrotron Radiation ◽  
Dft Calculation ◽  
Function Theory ◽  
Density Function Theory ◽  
Nuclear Resonance ◽  
Spectroscopic Evidence ◽  
Nickel Iron ◽  
Nuclear Resonance Vibrational Spectroscopy ◽  
Iron Hydride

Direct spectroscopic evidence for a hydride bridge in the Ni–R form of [NiFe] hydrogenase has been obtained using iron-specific nuclear resonance vibrational spectroscopy (NRVS). The Ni–H–Fe wag mode at 675 cm−1is the first spectroscopic evidence for a bridging hydride in Ni–R as well as the first iron-hydride-related NRVS feature observed for a biological system. Although density function theory (DFT) calculation assisted the determination of the Ni–R structure, it did not predict the Ni–H–Fe wag mode at ∼675 cm−1before NRVS. Instead, the observed Ni–H–Fe mode provided a critical reference for the DFT calculations. While the overall science about Ni–R is presented and discussed elsewhere, this article focuses on the long and strenuous experimental journey to search for and experimentally identify the Ni–H–Fe wag mode in a Ni–R sample. As a methodology, the results presented here will go beyond Ni–R and hydrogenase research and will also be of interest to other scientists who use synchrotron radiation for measuring dilute samples or weak spectroscopic features.

Density Function Theory Calculation of Crystal Properties and Electronic Structure of δ-Pu

2017 ◽  
Vol 727 ◽  
pp. 712-717
Author(s):  
Yuan Jiang Zhu ◽  
Yun Liang Gao
Keyword(s):  
Electronic Structure ◽  
Density Function ◽  
Elastic Properties ◽  
Density Functional ◽  
Function Theory ◽  
Local Density ◽  
Density Function Theory ◽  
Partial Density ◽  
Density Of State ◽  
Lattice Constants

In this paper, lattice constants, elastic properties and electronic structure of δ-Pu are investigated by means of plane wave pseudo-potential method (PWP) based on density function theory (DFT). A variety of density functional theory methods have been adopted to calculate the crystal structure and elastic property of δ-Pu, and it is found that the lattice constants, bulk modulus B, shear modulus G, Young's modulus E and Poisson's ratio ν calculated by spin polarization local density approximation (SP+LDA) method are in best agreement with experimental values. The electronic structure have been investigated within the framework of LDA+U, and the band structure, density of state (DOS) and partial density of state (PDOS) are calculated. Calculation results of elastic properties and electronic structure show that, δ-Pu shows obvious metallicity and well ductility, its electrons are strongly corrected and the DOS in the vicinity of the Fermi Level is mainly contributed by 5f electrons.

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