We invert a weighted average of the Fock equations to compute a local potential, which we use to form a zeroth-order local-exchange Hamiltonian for many-body perturbation theory. Convergence of the perturbation series is investigated for H2O, Be-2 and Ne, and the energies to second and fourth order are consistently closer to FCI than the corresponding Moller-Plesset energies, demonstrating that non-local exchange in the zeroth-order Hamiltonian is not necessary for a convergent perturbation theory. (C) 1998 Elsevier Science B.V. All rights reserved.
|Number of pages||7|
|Journal||Chemical Physics Letters|
|Publication status||Published - 30 Oct 1998|
- DENSITY-FUNCTIONAL THEORY
- CORRELATION ENERGIES
- MOLECULAR CALCULATIONS
- EXCHANGE-CORRELATION POTENTIALS