Electronic structure of electron-doped fullerenes

The electronic structures of C-60 fullerene complexes with two lithium atom s and nitrogen-substituted fullerenes are theoretically studied for the pur pose of their further comparison and for studying the isomer effect in thes e compounds. The electronic level spectrum of these compounds contains an i mpurity state lying in the energy band gap, caused by the presence of two e xtra electrons. The lithium fullerene complexes have one more feature-stron g level splitting-caused by the influence of positive lithium ions. The ban d gap width and average bond energy in the lithium fullerene complex are in fluenced by both the character of the polygon to which lithium atoms are co ordinated and the distance between the doped atoms. A similar, although irr egular, effect is also observed in nitrogen-substituted fullerenes.