Screened-exchange plus Coulomb-hole correlated Hartree-Fock energy bands for LiF

1975 ◽  
Vol 11 (4) ◽  
pp. 1600-1608 ◽  
Author(s):  
N. E. Brener
Keyword(s):  
Energy Bands ◽  
Hartree Fock ◽  
Coulomb Hole ◽  
Screened Exchange

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

A calculation of the phonon frequencies in sodium

1965 ◽  
Vol 283 (1392) ◽  
pp. 33-49 ◽  
Keyword(s):  
Phonon Scattering ◽  
Effective Interaction ◽  
Harmonic Approximation ◽  
Potential Method ◽  
Exchange Potential ◽  
Hartree Fock ◽  
Screened Exchange ◽  
Effective Attraction ◽  
Comparison Of The Results ◽  
Pseudo Potential

The phonon spectrum of sodium is calculated in the harmonic approximation. The effective interaction between the ions is separated into direct two-body forces between bare ions and effective attraction due to the presence of conduction electrons. Careful treatment of the two-phonon processes includes the calculation of the electron-phonon scattering based on the pseudo-potential method and the screening effects due to the interaction between electrons by the Hartree-Fock approximation with a screened exchange potential. Comparison of the results for sodium with neutron diffraction measurements and a previous calculation by Toya shows good agreement on the whole. It is hoped that this method may be applied to some other metals.

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.

Electron correlations in narrow energy bands

1963 ◽  
Vol 276 (1365) ◽  
pp. 238-257 ◽  
Keyword(s):  
Approximate Solution ◽  
Green Function ◽  
Approximate Model ◽  
Function Technique ◽  
Electron Correlations ◽  
Energy Bands ◽  
Hartree Fock ◽  
Correlation Problem ◽  
Main Effects ◽  
London Model

It is pointed out that one of the main effects of correlation phenomena in d - and f -bands is to give rise to behaviour characteristic of the atomic or Heitler-London model. To investigate this situation a simple, approximate model for the interaction of electrons in narrow energy bands is introduced. The results of applying the Hartree-Fock approximation to this model are examined. Using a Green function technique an approximate solution of the correlation problem for this model is obtained. This solution has the property of reducing to the exact atomic solution in the appropriate limit and to the ordinary uncorrelated band picture in the opposite limit. The condition for ferromagnetism of this solution is discussed. To clarify the physical meaning of the solution a two-electron example is examined.

Coulomb-Hole-Hartree-Fock functional

1994 ◽  
Vol 52 (4) ◽  
pp. 849-865 ◽  
Author(s):  
E. Clementi ◽  
D. W. M. Hofmann
Keyword(s):  
Hartree Fock ◽  
Coulomb Hole
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