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Epstein-Nesbet second-order perturbation treatment of dynamical electron correlation and ground state potential energy curve of Cr2

1997; Elsevier BV; Volume: 278; Issue: 4-6 Linguagem: Inglês

10.1016/s0009-2614(97)04014-1

1873-4448

Alexander O. Mitrushenkov, Paolo Palmieri,

Molecular Junctions and Nanostructures

The Cr2 potential energy curve is obtained by treating the dynamical correlation energy terms using a CI procedure based on determinants, equivalent to multi-reference second-order perturbation theory with the Epstein-Nesbet partition of the Hamiltonian. One of the advantages of this treatment is that the level shifts required for the equivalent Møller-Plesset type of treatment to eliminate intruder states and avoid divergences in the ground state second-order energy expression, are not required. Moreover, by truncating the reference space, the dynamical and the non-dynamical correlation energy is included also for the 3s, 3p electrons. The potentials are compared to experiment and to the most accurate theoretical potential curves in the literature.