Density functional calculation of complex atomic spectra

A density functional formalism, based on the Harbola-Sahni approach, is suggested for calculating the term energies associated with open-shell atomic configurations. The accuracy of the method is demonstrated for carbon and silicon electronic configurations corresponding to single- and double-electron excitations. The exchange-only energy values for multiplets associated with the ground-state configuration have also been calculated, the maximum error being 0.03% compared to the Hartree-Fock results. The error in the single- and double-electron excitation energies is within 4.5% compared to the experimental results.