The incorporation of quadratic convergence into open-shell self-consistent field equations

The quadratically convergent approach to solving the correct SCF equations for general open-shell systems (with orthogonal orbitals, i.e., multiconfiguration-SCF or Hartree-Fock) is derived and used to discuss other less complicated approaches. Representative calculations on He ^21[(1s) (2s)] and H_2O 2^1A_1 [(1a_1)^2 (2a_1)^2 (1b_1)^2 (1b^2)_2 (3a_1) (4a_1)] are reported.