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On the exactness of extended Koopmans' eigenvalues

✍ Scribed by B.T. Pickup; J.G. Snijders

Publisher
Elsevier Science
Year
1988
Tongue
English
Weight
436 KB
Volume
153
Category
Article
ISSN
0009-2614

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✦ Synopsis

We discuss conditions under which extended Koopmans' eigenvalues become exact ionisatlon potentials. Second-order perturbation theory is used to compare with known expressions involving relaxation contributions to the exact resulls. In two-electron systems all the EK elgenvalues are shown to be exact provided there are no vanishing natural occupancies in the exact reference state. In a finite basis model the EK eigenvalues do not match the exact IPs of the corresponding model Hamiltonian.

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