Application of thesubspace density functional theory to the excitation energies ofmolecules

Abstract

The performance of the subspace density functional theory in its local density approximation is investigated byapplications to the excitation energies of small molecules. Thedifferent schemes, concerning the choice of finite basis sets,for treating in a balanced way the ground and excited statecalculations, are discussed. Unlike the conventional atomcentred basis sets, we used off centred basis sets whoseparameters were determined by invoking the minimum principle forthe subspace energy. For the molecules under consideration(H2, HeH and LiH) such basis sets consisting only of s-typeGaussians, optimized for each subspace energy, were found toprovide a reasonable agreement of the excitation energiescomputed with those obtained by the configuration interactionmethods with extended basis sets.