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Orbitals from local RDMFT: Are they Kohn-Sham or Natural Orbitals?

Theophilou, I.; Lathiotakis, N.N.; Gidopoulos, N.I.; Rubio, A.; Helbig, N.

Orbitals from local RDMFT: Are they Kohn-Sham or Natural Orbitals? Thumbnail


I. Theophilou

N.N. Lathiotakis

A. Rubio

N. Helbig


Recently, an approximate theoretical framework was introduced, called local reduced density matrix functional theory (local-RDMFT), where functionals of the one-body reduced density matrix (1-RDM) are minimized under the additional condition that the optimal orbitals satisfy a single electron Schrödinger equation with a local potential. In the present work, we focus on the character of these optimal orbitals. In particular, we compare orbitals obtained by local-RDMFT with those obtained with the full minimization (without the extra condition) by contrasting them against the exact NOs and orbitals from a density functional calculation using the local density approximation (LDA). We find that the orbitals from local-RMDFT are very close to LDA orbitals, contrary to those of the full minimization that resemble the exact NOs. Since local RDMFT preserves the good quality of the description of strong static correlation, this finding opens the way to a mixed density/density matrix scheme, where Kohn-Sham orbitals obtain fractional occupations from a minimization of the occupation numbers using 1-RDM functionals. This will allow for a description of strong correlation at a cost only minimally higher than a density functional calculation.


Theophilou, I., Lathiotakis, N., Gidopoulos, N., Rubio, A., & Helbig, N. (2015). Orbitals from local RDMFT: Are they Kohn-Sham or Natural Orbitals?. The Journal of Chemical Physics, 143(5),

Journal Article Type Article
Acceptance Date Jul 27, 2015
Publication Date Aug 7, 2015
Deposit Date Aug 6, 2015
Publicly Available Date Sep 4, 2015
Journal Journal of Chemical Physics
Print ISSN 0021-9606
Electronic ISSN 1089-7690
Publisher American Institute of Physics
Peer Reviewed Peer Reviewed
Volume 143
Issue 5
Related Public URLs


Published Journal Article (773 Kb)

Copyright Statement
© 2015 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in The Journal of Chemical Physics 143, 054106 (2015) and may be found at

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