Konsequenzen des Koopmansschen Theorems in den Restricted Hartree Fock Methoden für open-shell-Systeme
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Consequences of Koopmans' theorem in the restricted Hartree Fock methods for open shell systems
The application of Koopmans' theorem to open shell systems shows — compared with closed shell systems — an important difference: a mixture of one-electron-states of theN-electron system is needed for the quantum mechanical description of the (N – 1)-electron system. The ionization potentials are obtained as eigenvalues of a special matrix. Equations for the elements of thisI-matrix were derived which are applicable to systems having a doublet ground state. The derivation was carried out for the procedures developed by Roothaan, Kruglyak, McWeeny, Longuet-Higgins, and Pople and Nesbet using the density matrix formalism. First numerical calculations suggest that the effects which are taken into account in the exact form of Koopmans' theorem are important.
Key wordsKoopmans' theorem application of ∼ to open shell systems Open shell systems, Koopmans' theorem in RHF methods for ∼
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