Aufbau derived from a unified treatment of occupation numbers in Hartree–Fock, Kohn–Sham, and natural orbital theories with the Karush–Kuhn–Tucker conditions for the inequality constraints ni≤1 and ni≥0

2010 ◽  
Vol 132 (19) ◽  
pp. 194108 ◽  
Author(s):  
K. J. H. Giesbertz ◽  
E. J. Baerends
Keyword(s):  
Inequality Constraints ◽  
Natural Orbital ◽  
Hartree Fock ◽  
Occupation Numbers

scholarly journals Application of Hartree-Fock theory of fluctuations to opacity calculation

1995 ◽  
Vol 13 (2) ◽  
pp. 255-269 ◽  
Author(s):  
T. Blenski ◽  
S. Morel
Keyword(s):  
Recent Measurement ◽  
Theoretical Spectrum ◽  
Hartree Fock ◽  
Occupation Numbers

The Hartree-Fock theory of fluctuations leading to simple formulae for configuration probabilities is used in a Detailed Configuration Accounting calculation of opacity in the case of an iron plasma. A direct Detailed Term Accounting method is also applied. The correlations of subshell occupation numbers, which are accounted for in the HF theory, show small effect on the theoretical spectrum corresponding to conditions of a recent measurement.

scholarly journals Electronic Properties of Carbon Nanobelts Predicted by Thermally-Assisted-Occupation DFT

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2224
Author(s):  
Sonai Seenithurai ◽  
Jeng-Da Chai
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Large Scale ◽  
Von Neumann Entropy ◽  
Electronic Systems ◽  
Functional Theory ◽  
Von Neumann ◽  
Hartree Fock ◽  
Prediction Of Properties ◽  
Occupation Numbers

Accurate prediction of properties of large-scale multi-reference (MR) electronic systems remains difficult for traditional computational methods (e.g., the Hartree–Fock theory and Kohn–Sham density functional theory (DFT)). Recently, thermally-assisted-occupation (TAO)-DFT has been demonstrated to offer reliable description of electronic properties of various large-scale MR electronic systems. Consequently, in this work, TAO-DFT is used to unlock the electronic properties associated with C-Belt[n] (i.e., the carbon nanobelts containing n fused 12-membered carbon rings). Our calculations show that for all the system sizes reported (n = 4–24), C-Belt[n] have singlet ground states. In general, the larger the size of C-Belt[n], the more pronounced the MR character of ground-state C-Belt[n], as evident from the symmetrized von Neumann entropy and the occupation numbers of active TAO-orbitals. Furthermore, the active TAO-orbitals are delocalized along the circumference of C-Belt[n], as evident from the visualization of active TAO-orbitals.

scholarly journals Natural Extension of Hartree–Fock Through Extremal 1-Fermion Information: Overview and Application to the Lithium Atom

2016 ◽  
Vol 230 (5-7) ◽  
Author(s):  
Carlos L. Benavides-Riveros ◽  
Christian Schilling
Keyword(s):  
Lithium Atom ◽  
Natural Extension ◽  
Exclusion Principle ◽  
Hartree Fock ◽  
Occupation Numbers

AbstractFermionic natural occupation numbers do not only obey Pauli's exclusion principle but are even stronger restricted by so-called generalized Pauli constraints. Whenever given natural occupation numbers lie on the boundary of the allowed region the corresponding

scholarly journals Implications of pinned occupation numbers for natural orbital expansions. II: rigorous derivation and extension to non-fermionic systems

2020 ◽  
Vol 22 (2) ◽  
pp. 023002
Author(s):  
Tomasz Maciążek ◽  
Adam Sawicki ◽  
David Gross ◽  
Alexandre Lopes ◽  
Christian Schilling
Keyword(s):  
Rigorous Derivation ◽  
Natural Orbital ◽  
Occupation Numbers ◽  
Fermionic Systems

scholarly journals Implications of pinned occupation numbers for natural orbital expansions: I. Generalizing the concept of active spaces

2020 ◽  
Vol 22 (2) ◽  
pp. 023001
Author(s):  
Christian Schilling ◽  
Carlos L Benavides-Riveros ◽  
Alexandre Lopes ◽  
Tomasz Maciążek ◽  
Adam Sawicki
Keyword(s):  
Natural Orbital ◽  
Occupation Numbers
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