Correlation potentials for molecular bond dissociation within the self-consistent random phase approximation

Maria Hellgren*, Daniel R. Rohr, E. K.U. Gross

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

72 Scopus citations

Abstract

Self-consistent correlation potentials for H 2 and LiH for various inter-atomic separations are obtained within the random phase approximation (RPA) of density functional theory. The RPA correlation potential shows a peak at the bond midpoint, which is an exact feature of the true correlation potential, but lacks another exact feature: the step important to preserve integer charge on the atomic fragments in the dissociation limit. An analysis of the RPA energy functional in terms of fractional charge is given which confirms these observations. We find that the RPA misses the derivative discontinuity at odd integer particle numbers but explicitly eliminates the fractional spin error in the exact-exchange functional. The latter finding explains the improved total energy in the dissociation limit.

Original languageAmerican English
Article number034106
JournalJournal of Chemical Physics
Volume136
Issue number3
DOIs
StatePublished - 21 Jan 2012
Externally publishedYes

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