A configuration‐averaged Hartree–Fock procedure

A configuration‐averaged Fock ( CAHF ) operator is developed within the restricted open‐shell formulation ( ROHF ) for the case of any number of open‐shell orbitals containing any number of electrons. The resulting orbitals and energies should be useful for those cases where there is a great degeneracy of states, either preventing self‐consistent field convergence, or negating the value of a pure state description itself. This procedure is compared with the hyper‐Hartree–Fock method of Slater and the grand canonical Hartree–Fock ansatz of Abdulnar, Linderberg, Öhrn, and Thulstrup.