A well-scaling natural orbital theory

Ralph Gebauer; Morrel H. Cohen; Roberto Car

doi:10.1073/pnas.1615729113

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arXiv · 1611.08692

A well-scaling natural orbital theory

Ralph Gebauer·Morrel H. Cohen·Roberto Car

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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.

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Ralph Gebauer, Morrel H. Cohen, Roberto Car. 2016-11-26. A well-scaling natural orbital theory. https://doi.org/10.1073/pnas.1615729113

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