We introduce a method for treating electronic correlation in which a correlation factor is optimized using Hylleraas variational perturbation theory. The factor is defined by a number of parameters which grows only linearly with system size. We test the theory on two-electron atoms using the shielded-nucleus Hamiltonian at zeroth order, obtaining - 2.9035 a.u. for helium. The convergence of the method is investigated, and energies and intracule densities are compared with accurate variational results. The application of the theory to an N-electron problem with a Hartree-Fock Hamiltonian at zeroth order is discussed. (C) 1999 Elsevier Science B.V. All rights reserved.
|Number of pages||7|
|Journal||Chemical Physics Letters|
|Publication status||Published - 10 Sep 1999|
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