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Theoretica chimica acta

, Volume 53, Issue 1, pp 55–63 | Cite as

Approximate calculation of the correlation energy for the closed and open shells

  • Renato Colle
  • Oriano Salvetti
Original Investigations

Abstract

A formula is derived for the approximate calculation of the correlation energy of both open and closed shell systems. The formula integrates a functional of the one- and two-electron density matrices, obtained from a wavefunction built up by one or several Slater determinants.

Some test calculations on the ground state of diatomic molecules at several internuclear distances and on many excited states of atoms and molecules show the goodness of this method.

Key words

Correlation energy Open shells 

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Copyright information

© Springer-Verlag 1979

Authors and Affiliations

  • Renato Colle
    • 1
  • Oriano Salvetti
    • 1
  1. 1.Laboratorio di Chimica Quantistica ed Energetica Molecolare del C.N.R.PisaItaly

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