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On the exactness of the extended Koopmans` theorem: Resolution of the paradox

Conference ·
OSTI ID:447601
 [1]
  1. Tulane Univ., New Orleans, LA (United States)
The generalized Koopmans theorem gives an estimate of the lowest ionization energy of an N-electron system. The approximate lowest ionization energy is obtained as the lowest eigenvalue of a generalized eigenvalue problem. It has been shown that the generalized Koopmans theorem predicts the exact lowest ionization energy for Coulomb systems. However, it has also been shown that in general no eigenvalue of the generalized Koopmans procedure corresponds to an exact ionization energy. This paradox is resolved by demonstrating that the lowest eigenvalue of the generalized Koopmans procedure does, in general, not exist for Coulomb systems. Nevertheless, it will also be shown that the generalized Koopmans approach gives ionization energies which are arbitrary close to the exact lowest ionization energy. The eigenvalues of the extended Koopmans theorem have an accumulation point given by the exact lowest ionization energy.
OSTI ID:
447601
Report Number(s):
CONF-960343--
Country of Publication:
United States
Language:
English

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