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A well-scaling natural orbital theory.

ABSTRACT: We introduce an energy functional for ground-state electronic structure calculations. Its variables are the natural spin-orbitals of singlet many-body wave functions and their joint occupation probabilities deriving from controlled approximations to the two-particle density matrix that yield algebraic scaling in general, and Hartree-Fock scaling in its seniority-zero version. Results from the latter version for small molecular systems are compared with those of highly accurate quantum-chemical computations. The energies lie above full configuration interaction calculations, close to doubly occupied configuration interaction calculations. Their accuracy is considerably greater than that obtained from current density-functional theory approximations and from current functionals of the one-particle density matrix.

SUBMITTER: Gebauer R

PROVIDER: S-EPMC5135379 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature

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A well-scaling natural orbital theory.

Gebauer Ralph R Cohen Morrel H MH Car Roberto R

Proceedings of the National Academy of Sciences of the United States of America 20161101 46

We introduce an energy functional for ground-state electronic structure calculations. Its variables are the natural spin-orbitals of singlet many-body wave functions and their joint occupation probabilities deriving from controlled approximations to the two-particle density matrix that yield algebraic scaling in general, and Hartree-Fock scaling in its seniority-zero version. Results from the latter version for small molecular systems are compared with those of highly accurate quantum-chemical c ...[more]

PMID: 27803328

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