Article

# Simple model for the spherically- and system-averaged pair density: Results for two-electron atoms

Physical Review A (Impact Factor: 2.81). 11/2004; 71(3). DOI: 10.1103/PhysRevA.71.032513

Source: arXiv

**ABSTRACT**

As shown by Overhauser and others, accurate pair densities for the uniform electron gas may be found by solving a two-electron scattering problem with an effective screened electron-electron repulsion. In this work we explore the extension of this approach to nonuniform systems, and we discuss its potential for density functional theory. For the spherically- and system-averaged pair density of two-electron atoms we obtain very accurate short-range properties, including, for nuclear charge $Z\ge 2$, ``on-top'' values (zero electron-electron distance) essentially indistinguishable from those coming from precise variational wavefunctions. By means of a nonlinear adiabatic connection that separates long- and short-range effects, we also obtain Kohn-Sham correlation energies whose error is less than 4 mHartree, again for $Z\ge 2$, and short-range-only correlation energies whose accuracy is one order of magnitude better. Comment: 9 pages, 6 figures (14 .eps files); revised version, to appear in Phys. Rev. A

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