  We analyze the various approaches to construct exchange-correlation
functionals which are able to describe states of definite spin multiplicity in
the DFT realm and outline the characteristics of possible functionals
consistent with the Kohn-Sham theory. To achieve this goal the unitary group
technique is applied to label many-electron states of definite total spin and
to calculate the corresponding analogs of the Roothaan coupling coefficients.
The possibility of using range separated Coulomb potential of electron-electron
interaction for constructing functionals discriminating multiplet states in the
d-shells is explored and a tentative system of state-specific functionals,
covering nontrivial correlations in d-shells of transition metal ions, is
proposed for the Fe^{2+} ions.
