Single-Fock-operator method for matrix Dirac-Fock self-consistent-field calculations on open-shell atoms

A generalized coupling operator method is employed to construct a single Fock operator for matrix Dirac-Fock self-consistent-field calculations on general open-shell multiplet states of atoms. The approach handles any number of open electronic shells. The matrix Dirac-Fock procedure is implemented with analytic basis sets of Gaussian-type functions for expansion of the large and small components of the Dirac four-spinors. Open-shell Dirac-Fock calculations in the single-Fock-operator formalism are performed on the ground and low-lying excited states of Li, B, Na, Al, K, Ga, and In.