TY  - JOUR
AU  - Theophilou, Iris
AU  - Lathiotakis, Nektarios N.
AU  - Gidopoulos, Nikitas I.
AU  - Rubio, Angel
AU  - Helbig, Nicole
TI  - Orbitals from local RDMFT: Are they Kohn-Sham or natural orbitals?
JO  - The journal of chemical physics
VL  - 143
IS  - 5
SN  - 1089-7690
CY  - Melville, NY
PB  - American Institute of Physics
M1  - FZJ-2015-05153
SP  - 054106
PY  - 2015
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000359377200010
C6  - pmid:26254641
DO  - DOI:10.1063/1.4927784
UR  - https://juser.fz-juelich.de/record/203141
ER  -