The application of the self-interaction correction to the local density Hartree-Fock calculations of atomic levels is discussed. For fixed-basis-set calculations a unified Hamiltonian is derived so that diagonalisation of the matrix of this operator gives both the occupied and excited levels. The formulation has advantages over the earlier ones where an orbital-dependent Hamiltonian must be solved separately for each state. Excited-state energies for eight light elements have been calculated by using this unified Hamiltonian approach and the results are in excellent agreement with experiment.
