The spin projected extended Hartree‐Fock equations for successive optimization of the orbitals are derived for the four‐electron case and applied to butadiene in the PPP approximation. The method shows an excellent convergence and gives 91.4% of the correlation energy for the given model‐Hamiltonian.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Physical and Theoretical Chemistry