Berlin 2001 – wissenschaftliches Programm

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MO: Molekülphysik

MO 7: Posters Wednesday: Theory: Structure and Dynamics

MO 7.10: Poster

Mittwoch, 4. April 2001, 12:30–15:00, AT3

Molecular Excitation Energies Computed with Kohn-Sham Orbitals and Exact Exchange Potentials — •Leif Veseth — Department of Physics, University of Oslo, 0316 Oslo, Norway

Exact local exchange potentials are computed for the diatomic molecules N2 and O2, based on expansions in terms of molecular orbitals. Kohn-Sham orbitals and orbital energies are obtained for the exact exchange potentials, with correlation effects neglected. Limited configuration interaction calculations are performed based on the Kohn-Sham orbitals, and are found to yield accurate excitation energies for a series of singly excited states, in particular for N2. Clearly inferior results are obtained from similar calculations by use of Hartree-Fock orbitals. Thus, Kohn-Sham orbitals obtained with exact exchange potentials tend to have an interesting potential as basis for sophisticated many-body methods.