Orbital-dependent second-order scaled-opposite-spin correlation functionals in the optimized effective potential method

Abstract

The performance of correlated optimized effective potential (OEP) functionals based on the spin-resolved second-order correlation energy is analyzed. The relative importance of singly- and doubly- excited contributions as well as the effect of scaling the same- and opposite- spin components is investigated in detail comparing OEP results with Kohn-Sham (KS) quantities determined via an inversion procedure using accurate ab initio electronic densities. Special attention is dedicated in particular to the recently proposed scaled-opposite-spin OEP functional [I. Grabowski, E. Fabiano and F. Della Sala, Phys. Rev. B, 87, 075103, (2013)] which is the most advantageous from a computational point of view. We find that for high accuracy a careful, system dependent, selection of the scaling coefficient is required. We analyze several size-extensive approaches for this selection. Finally, we find that a composite approach, named OEP2-SOSh, based on a post-SCF rescaling of the correlation energy can yield high accuracy for many properties, being comparable with the most accurate OEP procedures previously reported in the literature but at substantially reduced computational effort.

14 pages, 4 figures

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Cited by in corpus (7)

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• Self-consistent range-separated density-functional theory with second-order perturbative correction via the optimized-effective-potential method
• Methods to generate the reference total and Pauli kinetic potentials
• Hartree potential dependent exchange functional
• Random-Phase Approximation in Many-Body Noncovalent Systems: Methane in a Dodecahedral Water Cage
• Accurate non-covalent interaction energies via an efficient MP2 scaling procedure