Critical analysis of the Colle-Salvetti model for electron correlation in closed shell systems: pair correlations

2000 ◽  
Vol 98 (21) ◽  
pp. 1811-1821 ◽  
Author(s):  
S. Caratzoulas, P. J. Knowles
Keyword(s):  
Electron Correlation ◽  
Critical Analysis ◽  
Closed Shell ◽  
Pair Correlations

Correlation Funktions of a System with Different Temperatures of the Particle Components

1964 ◽  
Vol 19 (13) ◽  
pp. 1447-1451 ◽  
Author(s):  
G. Ecker ◽  
W. Kröll
Keyword(s):  
Correlation Function ◽  
Electron Correlation ◽  
Pair Correlation ◽  
Bbgky Hierarchy ◽  
Ion Pair ◽  
Pair Correlations ◽  
The Poisson Equation ◽  
Average Potential ◽  
Different Temperatures ◽  
Dressed Particles

We consider a plasma consisting of particle components with different temperatures. The components are uniformly distributed in the configuration space and MAXWELLIAN in the velocity space. Pair correlations are assumed to be small and higher order correlations negligible. It is shown from the BBGKY-hierarchy that the influence of the electrons on the ion kinetics can be taken into account by treating the ions as dressed particles. The hierarchy for these dressed particles provides the ion-ion correlation function. The electron-ion pair correlation is calculated from the POISSON equation using the ion-ion correlation and relating the electron-ion pair distribution to the average potential. By the same procedure we derive the electron-electron correlation making use of the electron-ion correlation. The results are compared with those of other authors.

Simplified Non-Empirical Unrestricted Hartree-Fock Approximation (SUHF) for the Calculation of Electronic Ground State Properties of Molecules with Closed and Open Valence Shells. I. Method

1993 ◽  
Vol 48 (7) ◽  
pp. 829-833
Author(s):  
Wolfhard Koch
Keyword(s):  
Electron Correlation ◽  
Ground State ◽  
Atomic Orbital ◽  
Closed Shell ◽  
Open Shell ◽  
Polyatomic Molecules ◽  
Correlation Effects ◽  
Hartree Fock ◽  
Electron Correlation Effects ◽  
Electronic Ground

Abstract Focusing on relative stabilities of electronic states with different spin multiplicities of polyatomic molecules, a simplified unrestricted Hartree-Fock (SUHF) procedure is described. Using different orbitals for different spins (DODS), electron correlation effects of both closed-shell and open-shell systems are expected to be taken into account in the simplest way. While working within a symmetrically orthogonalized (Löwdin) basis we make use of the NDDO approximation (neglect of diatomic differential overlap) concerning the evaluation of electron repulsion and nuclear attraction integrals. Originally, a locally orthogonalized all-electron atomic orbital set of Slater type is considered. The approximation method is completely non-empirical. Rotational invariance is fully retained.

Pair Correlations in Closed‐Shell Systems

1964 ◽  
Vol 40 (1) ◽  
pp. 80-85 ◽  
Author(s):  
M. Krauss ◽  
A. W. Weiss
Keyword(s):  
Closed Shell ◽  
Pair Correlations
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