Energy Spectrum and Optical Absorption Spectrum of Fullerene C.sub.28 within the Hubbard Model

Anticommutator Green's functions and energy spectra of the C.sub.28 fullerene and the endohedral Zr@C.sub.28 fullerene with the symmetry group T.sub.d are obtained within the Hubbard model in the approximation of static fluctuations. Using the methods of group theory, the classification of energy states is carried out, and the allowed transitions in the energy spectra of C.sub.28 and Zr@C.sub.28 molecules are determined.