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Local correlation potentials from Brueckner coupled-cluster theory.
1Center of Theoretical Chemistry, Arhus University, Denmark. and@chem.au.dk
The Journal of Chemical Physics
|July 23, 2005
Summary
Local correlation potentials were derived from nonlocal potentials for rare gases and CO. These potentials, composed of pure correlation and relaxation parts, accurately represent atomic shell structures and correlate well with Brueckner determinants.
Area of Science:
- Quantum Chemistry
- Computational Physics
Background:
- Nonlocal Brueckner coupled-cluster potentials are crucial for accurate electronic structure calculations.
- Understanding local correlation potentials is key to simplifying complex quantum chemical models.
Purpose of the Study:
- To derive local correlation potentials from nonlocal ones for rare-gas atoms and CO.
- To analyze the structure and components of these local potentials.
- To validate the accuracy of the derived local potentials by comparing them to established methods.
Main Methods:
- Derivation of local correlation potentials from nonlocal Brueckner coupled-cluster potentials.
- Analysis of the derived potentials' structure, including pure correlation and relaxation components.
- Evaluation using determinantal overlap and one-electron properties.
Main Results:
- Local correlation potentials were successfully obtained for He, Ne, Ar, and CO.
- The potentials exhibit distinct oscillating behavior near nuclei, reflecting atomic shell structure.
- Components of the local potentials showed monotonous decrease, with step structures for Ne and Ar.
- Orbitals from local potentials closely matched the Brueckner determinant.
Conclusions:
- The derived local correlation potentials effectively capture atomic shell structure.
- The study confirms the close correspondence between local potentials and Brueckner determinants.
- This work validates the approximation of correlated wave functions using local potentials.