Relativistic calculations on the alkali atoms by a modified Hartree-Fock method

A relativistic Hartree-Fock method, being a slight modification of the conventional formulation and closely related to the approach of Cowan and Griffin (1976) is examined in calculations for the Li, Na, K, Rb and Cs isoelectronic series. Relativistic corrections to the total and orbital energies, expectation values of rn, excitation energies, fine-structure splittings (calculated as energy differences) and oscillator strengths are very close to the corresponding values obtained by means of the Dirac-Fock method. A comparison with existing experimental data shows that the method gives reliable estimates of the transition energies and oscillator strengths, especially for highly ionised atoms.