Abstract
The originally proposed first-order correlation orbital method (L. Adamowicz and R.J. Bartlett, J. Chem. Phys. 86 (1987) 6314) has been extended in order to include the MCSCF zeroth-order wave function. The present method is based on the perturbation theory with the zeroth-order Hamiltonian suggested by Andersson (J. Phys. Chem. 94 (1990) 5483). In the present work we restrict our consideration to the simplest case, i.e. the two-electron/two-orbital MCSCF reference wave function. The procedure is tested on the model system - lithium dimer - at a variety of interatomic distances. The results show that the calculated second-order correlation energy as well as the value of the second-order Hylleraas functional in the reduced space of the first-order correlation orbitals behave correctly upon dissociation of the system.
Original language | English (US) |
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Pages (from-to) | 483-490 |
Number of pages | 8 |
Journal | Chemical Physics Letters |
Volume | 183 |
Issue number | 6 |
DOIs | |
State | Published - Sep 13 1991 |
ASJC Scopus subject areas
- General Physics and Astronomy
- Physical and Theoretical Chemistry