scholarly journals Electronic Structure and Momentum Density of BaO and BaS

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
R. Kumar ◽  
B. K. Sharma ◽  
G. Sharma
Keyword(s):  
Electronic Structure ◽  
Charge Transfer ◽  
Momentum Density ◽  
Compton Profile ◽  
Density Profiles ◽  
Compound Formation ◽  
Atomic Orbitals ◽  
Hartree Fock ◽  
Valence Electron Density ◽  
Electron Density Profiles

The electronic structure and electron momentum density distribution in BaO and BaS are presented using Compton spectroscopy. The first-ever Compton profile measurements on polycrystalline BaO and BaS were performed using 59.54 keV gamma-rays. To interpret the experimental data, we have computed the theoretical Compton profiles of BaO and BaS using the linear combination of atomic orbitals method. In the present computation, the correlation scheme proposed by Perdew-Burke-Ernzerhof and the exchange scheme of Becke were considered. The hybrid B3PW and Hartree-Fock based profiles were also computed for both compounds. The ionic configurations are performed to estimate the charge transfer on compound formation, and the present study suggests charge transfer from Ba to O and S atoms. On the basis of equal-valence-electron-density profiles, it is found that BaO is more ionic as compared to BaS.

scholarly journals Electron Momentum Density and Phase Transition in ZnS

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
N. Munjal ◽  
M. C. Mishra ◽  
G. Sharma ◽  
B. K. Sharma
Keyword(s):  
Phase Transition ◽  
Density Functional ◽  
Momentum Density ◽  
Compton Profile ◽  
Functional Theory ◽  
Electron Momentum ◽  
Electron Momentum Density ◽  
Atomic Orbitals ◽  
Valence Electron Density ◽  
Good Agreement

The electron momentum density distribution and phase transition in ZnS are reported in this paper. The calculations are performed on the basis of density functional theory (DFT) based on the linear combination of atomic orbitals (LCAO) method. To compare the theoretical Compton profile, the measurement on polycrystalline ZnS has been made using a Compton spectrometer employing 59.54 keV gamma rays. The spherically averaged theoretical Compton profile is in agreement with the measurement. On the basis of equal valence-electron-density Compton profiles, it is found that ZnS is less covalent as compared to ZnSe. The present study suggests zincblende (ZB) to rocksalt (RS) phase transition at 13.7 GPa. The calculated transition pressure is found in good agreement with the previous investigations.

Electron Momentum Density of Nanoparticles ZrO2: A Compton Profile Study

2021 ◽  
pp. 2150018
Author(s):  
Sameen F. Mohammed ◽  
Abdulhadi Mirdan Ghaleb ◽  
Esam S. Ali
Keyword(s):  
Charge Transfer ◽  
Gamma Rays ◽  
Mechanical Milling ◽  
Momentum Density ◽  
Compton Profile ◽  
Ionic Model ◽  
Compound Formation ◽  
Electron Momentum ◽  
Profile Study ◽  
Xrd And Tem

This work investigates the electronic momentum density (EMD) distribution in nanosize zirconia (ZrO2) using the technique of Compton scattering. The ZrO2 nanoparticles (11.2[Formula: see text]nm) are synthesized of mechanical milling and characterized by SEM, XRD and TEM probes. The Compton profile [Formula: see text] of nanoZrO2 is measured by Compton spectrometer 59.54[Formula: see text]KeV Gamma rays (Americium-241) source. The study finds out that EMD in nanoZrO2 is narrower comparing in case bulk ZrO2. This study adopts the ionic-model-based free atom [Formula: see text] calculation for many configurations (Zr)[Formula: see text](O[Formula: see text])2 ([Formula: see text]) to measure the charge transfer (CT) on the compound formation. According to this study’s findings, CT values in these materials are ranged from 1.5 to 1.0 electrons from Zr to O atom.

Compton Scattering and Electronic Properties of Tungsten Ditelluride

2013 ◽  
Vol 209 ◽  
pp. 107-110 ◽  
Author(s):  
Gunjan Arora ◽  
B.L. Ahuja
Keyword(s):  
Density Functional Theory ◽  
Density Of States ◽  
Density Functional ◽  
Local Density ◽  
Measured Data ◽  
Compton Profile ◽  
Energy Bands ◽  
Functional Theory ◽  
Atomic Orbitals ◽  
Hartree Fock

We report the first ever isotropic experimental Compton profile of tungsten ditelluride using 20 Ci 137Cs Compton spectrometer. To compare our experimental data, we have also computed the Compton profiles, energy bands, density of states and band gap using Hartree-Fock and density functional theory within linear combination of atomic orbitals. The measured data is found to be in better accordance with the generalised gradient approximation of density functional theory than Hartree-Fock and local density approximation. We have discussed the nature of bonding in WTe2 using energy bands and density of states.

Direct-space analysis of the electronic structure of the YBa2Cu3O6 and YBa2Cu3O7 crystals

2002 ◽  
Vol 80 (3) ◽  
pp. 235-244 ◽  
Author(s):  
Fausto Cargnoni ◽  
Marco Scavini
Keyword(s):  
Electronic Structure ◽  
Specific Cell ◽  
Electron Localization ◽  
Superconducting Transition ◽  
Complementary Information ◽  
Superconducting Cuprates ◽  
Atomic Orbitals ◽  
Hartree Fock ◽  
Atomic Properties ◽  
Pseudopotential Calculations

The electronic structure of the YBa2Cu3O6 and YBa2Cu3O7 crystals is investigated by means of fully periodic-restricted Hartree–Fock LCAO (linear combination of atomic orbitals) pseudopotential calculations. To give a detailed description of the bonding and atomic properties of the materials studied we selected the quantum theory of atoms in molecules approach, and complementary information is obtained from the analysis of the electron localization function in specific cell regions. The main features of the YBa2Cu3O6 and YBa2Cu3O7 crystals' electron densities are detailed and compared with available experimental data. Since the superconducting transition requires oxidation of the YBa2Cu3O6 crystal, we focused on the electronic rearrangements related to the inclusion of oxygen. Cu–O planes, probably responsible for the superconducting transition, exhibit peculiar electronic properties.Key words: superconducting cuprates, electron density, ab initio calculations.

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.

Study of charge transfer in FeTi

1983 ◽  
Vol 41 ◽  
pp. 296-297
Author(s):  
J. Taft∅
Keyword(s):  
Charge Transfer ◽  
Charge Distribution ◽  
Electron Scattering ◽  
Periodic System ◽  
Electron Distribution ◽  
Scattering Amplitude ◽  
Transition Elements ◽  
Hartree Fock ◽  
Cscl Structure ◽  
The Right

It is well known that for reflections corresponding to large interplanar spacings (i.e., sin θ/λ small), the electron scattering amplitude, f, is sensitive to the ionicity and to the charge distribution around the atoms. We have used this in order to obtain information about the charge distribution in FeTi, which is a candidate for storage of hydrogen. Our goal is to study the changes in electron distribution in the presence of hydrogen, and also the ionicity of hydrogen in metals, but so far our study has been limited to pure FeTi. FeTi has the CsCl structure and thus Fe and Ti scatter with a phase difference of π into the 100-ref lections. Because Fe (Z = 26) is higher in the periodic system than Ti (Z = 22), an immediate “guess” would be that Fe has a larger scattering amplitude than Ti. However, relativistic Hartree-Fock calculations show that the opposite is the case for the 100-reflection. An explanation for this may be sought in the stronger localization of the d-electrons of the first row transition elements when moving to the right in the periodic table. The tabulated difference between fTi (100) and ffe (100) is small, however, and based on the values of the scattering amplitude for isolated atoms, the kinematical intensity of the 100-reflection is only 5.10-4 of the intensity of the 200-reflection.

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