Fragmentation of natural orbital occupation numbers‐based diagnostic of differential multireference character in complexes with hydrogen bonds

2020 ◽  
Author(s):  
Martin Šulka ◽  
Matúš Dubecký
Keyword(s):  
Hydrogen Bonds ◽  
Natural Orbital ◽  
Occupation Numbers ◽  
Orbital Occupation

ELECTRONIC STRUCTURE OF YBa2(Cu1−xFex)3O7

1993 ◽  
Vol 07 (01n03) ◽  
pp. 170-173
Author(s):  
V. CRISAN ◽  
A. VERNES ◽  
V. POPESCU ◽  
L. DULCA ◽  
D. KAPUSI
Keyword(s):  
Electronic Structure ◽  
Fermi Level ◽  
Density Of States ◽  
Copper Atom ◽  
Opposite Effect ◽  
Recursive Method ◽  
Electron Orbital ◽  
Occupation Numbers ◽  
Model Hamiltonian ◽  
Orbital Occupation

The density of states (DOS) at the Fermi level, (EF), for the 123 superconductor doped with iron was computed. The LCAO model hamiltonian and the Haydock recursive method were used. The iron atoms were located only in one of the copper atom positions Cu1 or Cu2 or in both of them with the same probability. The substitution of Fe in Cu1 positions increased the DOS at the Fermi level as x increased but the substitutions in the Cu2 positions had an opposite effect. In both cases the O2 and O3 positions are inequivalent. When the replacement of copper atoms is produced with the same probability in Cu1 and Cu2 positions the DOS at EF decreases as x increases. The DOS at EF and the electron orbital occupation numbers for O2 and O3 have the same behaviour as the lattice parameters, a and b.

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
Sign in / Sign up

Export Citation Format

Share Document