Density functional for short-range correlation: Accuracy of the random phase approximation for isoelectronic energy changes

Physical Review B 61, 16430 - 16439 (2000)

Density functional for short-range correlation: Accuracy of the random phase approximation for isoelectronic energy changes

Z. Yan, J.P. Perdew, S. Kurth

Within a density-functional context, the random-phase approximation (RPA) for the correlation energy makes a short-range error that is well suited for correction by a local spin density or generalized-gradient approximation (GGA). Here we construct a GGA for the short-range correction, following the same reliable procedure used earlier to construct the GGA for the whole exchange-correlation energy: real-space cutoff of the spurious long-range contribution to the gradient expansion of the hole around an electron. The resulting density functional is nearly local and predicts a substantial correction to the RPA correlation energy of an atom but very small corrections to the RPA atomization energy of a molecule, which may by itself come close to “chemical accuracy” and to the RPA surface energy of a metal. A by-product of this work is a density functional for the system-averaged correlation hole within RPA.

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http://dx.doi.org/10.1103/PhysRevB.61.16430

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