Spherically Averaged Densities as Basic DFT Variables

In a novel version of density functional theoryDensity functional theory proposed by Theophilou the basic variables are spherically symmetric densitiesSpherically symmetric densities. This theory has been extended using constrained searchConstrained search. A novel representability problem the ’set-representability problem has been detected and solved proposing the spherical potential functional theorySpherical potential functional theory. This chapter summarizes these new theories and presents virial theoremVirial theorem and hierarchy of equationsHierarchy of equations.