Electronic Structure of Electron-Doped Fullerenes

The electronic structures of C₆₀ fullerene complexes with two lithium atoms and nitrogen-substituted fullerenes are theoretically studied for the purpose of their further comparison and for studying the isomer effect in these compounds. The electronic level spectrum of these compounds contains an impurity state lying in the energy band gap, caused by the presence of two extra electrons. The lithium fullerene complexes have one more feature - strong level splitting - caused by the influence of positive lithium ions. The band gap width and average bond energy in the lithium fullerene complex are influenced by both the character of the polygon to which lithium atoms are coordinated and the distance between the doped atoms. A similar, although irregular, effect is also observed in nitrogen-substituted fullerenes.