## Abstract

An approximation for the exchange-correlation energy of reduced-density-matrix-functional theory was recently derived from a study of the homogeneous electron gas [N. N. Lathiotakis, N. Helbig, and E. K. U. Gross, Phys. Rev. B 75, 195120 (2007)]. In the present work, we show how this approximation can be extended appropriately to finite systems, where the Wigner Seitz radius r _{s}, the parameter characterizing the constant density of the electron gas, needs to be replaced. We apply the functional to a variety of molecules at their equilibrium geometry and also discuss its performance at the dissociation limit. We demonstrate that, although originally derived from the uniform gas, the approximation performs remarkably well for finite systems.

Original language | American English |
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Article number | 064109 |

Journal | Journal of Chemical Physics |

Volume | 130 |

Issue number | 6 |

DOIs | |

State | Published - 2009 |

Externally published | Yes |

### Bibliographical note

Funding Information:This work was supported in part by the Deutsche Forschungsgemeinschaft within the program SPP 1145, by the EXCITING Research and Training Network, and by the EU’s Sixth Framework Program through the Nanoquanta Network of Excellence (Grant No. NMP4-CT-2004-500198).