Specific features of determination of the energy of excited electronic states in the formalism of density functional theory

Possibilities for application of the theory of subspaces to determination of the energy of excited electronic states are studied in terms of density functional formalism. Specific features of computer implementation of the theory in a basis of spherical Gaussian functions, whose parameters are determined by minimizing the energy of the corresponding subspace of states, are discussed. The results of calculation of the energy of excited states and the excitation energies of simple atoms and molecules are presented to demonstrate the potential of the approach.