AN ALGEBRAIC-METHOD FOR SOLVING HARTREE-FOCK EQUATIONS .2. OPEN-SHELLMOLECULAR-SYSTEMS

This paper is the follow-up of an earlier one. It presents (i) the sys tem of nonlinear algebraic equations of the Algebraic Method correspon ding to the Hartree-Fock-Pople-Nesbet Approach; and (ii) a systematic study of the variations of the energy of an Unrestricted-Hartree-Fock (UHF) type wave-function as a function of molecular orbitals, for some molecular systems. The results show explicitly for NB, OH and CH the existence of two Hartree-Fock (HF) minimum points with the same spatia l symmetry and satisfying the aufbau occupancy rule.