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.

scholarly journals Effect of Hartree–Fock pseudopotentials on local density functional theory calculations

2018 ◽  
Vol 20 (27) ◽  
pp. 18844-18849 ◽  
Author(s):  
Hengxin Tan ◽  
Yuanchang Li ◽  
S. B. Zhang ◽  
Wenhui Duan
Keyword(s):  
Density Functional Theory ◽  
Band Gap ◽  
Density Functional ◽  
Local Density ◽  
Density Functional Theory Calculations ◽  
Optimal Choice ◽  
Functional Theory ◽  
Hartree Fock ◽  
Local Density Functional Theory ◽  
Local Density Functional

Optimal choice of the element-specific pseudopotential improves the band gap.

Compton Profile Study of Aluminium Nitride

2007 ◽  
Vol 62 (12) ◽  
pp. 703-710 ◽  
Author(s):  
Vimal Vyas ◽  
Yogesh Chandra Sharma ◽  
Vinod Purvia ◽  
Narayan Lal Heda ◽  
Yamini Sharma ◽  
...  
Keyword(s):  
Density Functional ◽  
Population Analysis ◽  
Theoretical Data ◽  
Aluminium Nitride ◽  
Compton Profile ◽  
Energy Bands ◽  
Functional Theory ◽  
Hartree Fock ◽  
Ionic Nature ◽  
Γ Rays

In this paper we report the ab-initio theoretical Compton profiles of aluminium nitride (AlN) in the framework of the Hartree-Fock, density functional theory and hybridization of Hartree-Fock to density functional theories using the CRYSTAL03 code. To compare our first ever theoretical data, we have also measured the isotropic Compton profile of AlN, using 59.54 keV γ -rays. The Hartree- Fock scheme-based Compton profile agrees better with the experiment than the other theories. The energy bands, density of states and Mulliken’s population analysis, using the CRYSTAL03 code, are also reported. Our band structure calculations show a large band gap, while Mulliken’s population analysis shows the ionic nature of bonding in AlN.

Quadrupole polarizabilities and Sternheimer antishielding factors in the density functional theory

1982 ◽  
Vol 60 (2) ◽  
pp. 210-221 ◽  
Author(s):  
M. J. Stott ◽  
E. Zaremba ◽  
D. Zobin
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Correlation Energy ◽  
Local Density ◽  
Closed Shell ◽  
Energy Functional ◽  
Functional Theory ◽  
Hartree Fock ◽  
Shielding Factor ◽  
The Density Functional Theory

The quadrupole polarizability and Sternheimer antishielding factor have been calculated for selected closed-shell atoms and ions using the density functional theory. In most cases, the results agree favourably with coupled Hartree–Fock calculations. However, for atoms with valence (d-shells the local density approximation used in the calculations is found to be inadequate. Our results suggest that refinements to the exchange-correlation energy functional are required in order to obtain accurate values for the polarizability and shielding factor of (d-shell atoms within a density functional approach.

A Charge Compton Profile Study of Ni2MnGa: Theory and Experiment

2008 ◽  
Vol 52 ◽  
pp. 181-186
Author(s):  
G. Ahmed ◽  
B.L. Ahuja ◽  
N.L. Heda ◽  
Vinit Sharma ◽  
A. Rathor ◽  
...  
Keyword(s):  
Density Functional ◽  
Local Density ◽  
Full Potential ◽  
Compton Profile ◽  
Energy Bands ◽  
Generalized Gradient ◽  
Plane Wave Method ◽  
Charge Densities ◽  
Hartree Fock ◽  
A Charge

We present the first ever theoretical and experimental charge Compton profiles of Ni2MnGa Heusler alloy. The measurements have been made using magnetic Compton spectrometer at SPring8, Japan. The Compton profiles and energy bands have been computed using Hartree-Fock, density functional theory with local density and generalized gradient approximations. It is seen that the Hartree-Fock based Compton profile is relatively in better agreement with the experimental profiles. In addition, we also report the energy bands, density of states and valence charge densities using full potential linearized augmented plane-wave method.

DFT Study of the Monocyclic and Bicyclic Ring Geometries of C20

1995 ◽  
Vol 408 ◽  
Author(s):  
Zhiqiang Wang ◽  
Paul Day ◽  
Ruth Pachter
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Local Density ◽  
Single Point ◽  
Dft Study ◽  
Functional Theory ◽  
Functional Approximation ◽  
Hartree Fock ◽  
Point Calculation ◽  
Local Density Functional

AbstractThe monocyclic and bicyclic ring geometries of C20 are optimized using both the local density functional approximation (LDA) and gradient-corrected density functional theory (BLYP). The energy of the bicyclic ring is found to be higher than that of the monocyclic ring in both LDA and BLYP calculations. The BLYP results confirm the previous single point calculation based on Hartree-Fock geometries[1], which is in favor of the monocyclic ring geometry, while the LDA results still favor the cage geometry. LDA frequencies of both ring geometries are also presented.

Structural, Electronic and Dynamical Properties of Binary Alloy Zr-Al Using Density Functional Theory

2016 ◽  
Vol 1141 ◽  
pp. 204-209
Author(s):  
Hardik L. Kagdada ◽  
Hiral J. Trivedi ◽  
Sharad B. Pillai ◽  
Narayan N. Som ◽  
Prafulla K. Jha
Keyword(s):  
Density Functional Theory ◽  
Density Of States ◽  
Density Functional ◽  
Phonon Dispersion ◽  
Local Density ◽  
Theoretical Data ◽  
Al Alloy ◽  
Electronic Band ◽  
Functional Theory ◽  
End Members

The structural, electronic, dynamical and thermodynamical properties of binary Zr-Al alloy (Zr3Al) with its end members are studied using the first principles calculations based on density functional theory. We have employed the Perdew-Zunger local density approximation as the exchange correlational functional in these calculations. There is a good agreement between present and available and experimental and other theoretical data. The calculated electronic band structure and density of states suggest that the Zr-Al alloy and its end members are metallic in nature consistent with earlier studies. Full phonon dispersion curves and phonon density of states are also calculated which show the dynamical stability of these compounds at zero pressure. The temperature dependence of the thermodynamical functions are also presented.

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