Brueckner orbitals, Dyson orbitals, and correlation potentials

J. V. Ortiz

doi:10.1002/qua.20204

First-order intermolecular interaction energies from coupled-cluster Brueckner orbitals

The Journal of Chemical Physics ◽

10.1063/1.481309 ◽

2000 ◽

Vol 112 (16) ◽

pp. 6949-6952 ◽

Cited By ~ 23

Author(s):

Andreas Heßelmann ◽

Georg Jansen

Keyword(s):

Intermolecular Interaction ◽

Coupled Cluster ◽

Interaction Energies ◽

First Order ◽

Brueckner Orbitals

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Ab initio Correlation Effects in Density Functional Theories: An Electron-Distribution-Based Study for Neon

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20051157 ◽

2005 ◽

Vol 70 (8) ◽

pp. 1157-1176 ◽

Cited By ~ 5

Author(s):

Karol Jankowski ◽

Ireneusz Grabowski ◽

Krzysztof Nowakowski ◽

Jan Wasilewski

Keyword(s):

Ab Initio ◽

Density Functional ◽

Physical Nature ◽

Correlation Effects ◽

Functional Theory ◽

Exchange Correlation ◽

Hartree Fock ◽

Brueckner Orbitals ◽

Local Gradient ◽

The Impact

We have briefly reviewed the idea of studies aiming at such a bridging of the methodological gap between ab initio methods (or wave function theory (WFT)) and density functional theory (DFT) that would afford carrying over results concerning details of the structure of correlation effects from one method to the other. Special attention is paid to the problem of coverage of the WFT correlation effects by the exchange-correlation functionals of DFT. A short survey of the concept of supplementing energy-based investigations in this field by electron-density-based studies is given and illustrated by results for the Ne atom. DFT densities are generated for representatives of all four generations of presently used exchange-correlation functionals, including the recently developed orbital-dependent one. These densities are compared with WFT densities calculated at the MP2, MP3, and Brueckner determinant levels. It is found that the exchange-only parts of the local, gradient-corrected, and hybrid functionals account for the bulk of WFT correlation effects. The impact of the associated correlation functionals is very small and their physical nature is not quite clear. The situation is different for the orbital-dependent functional for which the exchange-only functional provides an almost exact description of the Hartree-Fock density. Here, the correlation effects are entirely represented by the correlation functional. Attention is also paid to the suitability of Kohn-Sham orbitals for the description of WFT correlation effects and to their presumptive similarity with Brueckner orbitals.

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