title: Random-Phase Approximation Methods.
abstract: Random-phase approximation (RPA) methods are rapidly emerging as cost-effective validation tools for semilocal density functional computations. We present the theoretical background of RPA in an intuitive rather than formal fashion, focusing on the physical picture of screening and simple diagrammatic analysis. A new decomposition of the RPA correlation energy into plasmonic modes leads to an appealing visualization of electron correlation in terms of charge density fluctuations. Recent developments in the areas of beyond-RPA methods, RPA correlation potentials, and efficient algorithms for RPA energy and property calculations are reviewed. The ability of RPA to approximately capture static correlation in molecules is quantified by an analysis of RPA natural occupation numbers. We illustrate the use of RPA methods in applications to small-gap systems such as open-shell d- and f-element compounds, radicals, and weakly bound complexes, where semilocal density functional results exhibit strong functional dependence.
authors.affiliation: Department of Chemistry, University of California, Irvine, California 92697-2025; email: guo.chen@uci.edu , filipp.furche@uci.edu.
authors.forename: Guo P
authors.initials: GP
authors.lastname: Chen
authors.affiliation: Department of Chemistry, University of California, Irvine, California 92697-2025; email: guo.chen@uci.edu , filipp.furche@uci.edu.
authors.forename: Vamsee K
authors.initials: VK
authors.lastname: Voora
authors.affiliation: Department of Chemistry, University of California, Irvine, California 92697-2025; email: guo.chen@uci.edu , filipp.furche@uci.edu.
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Agee
authors.affiliation: Department of Chemistry, University of California, Irvine, California 92697-2025; email: guo.chen@uci.edu , filipp.furche@uci.edu.
authors.forename: Sree Ganesh
authors.initials: SG
authors.lastname: Balasubramani
authors.affiliation: Department of Chemistry, University of California, Irvine, California 92697-2025; email: guo.chen@uci.edu , filipp.furche@uci.edu.
authors.forename: Filipp
authors.initials: F
authors.lastname: Furche
keywords: density functional theory; electron correlation; electronic structure theory; noncovalent interactions; random-phase approximation; small-gap systems