Electronic structures of endohedral N@C60, O@C60 and F@C60

Discrete-variational local density functional calculations on endohedral N@C60, O@C60 and F@C60 are performed. In contrast to level lowering upon endohedral metal atom doping, all the C60-derived levels are very slightly elevated (<0.2 eV) upon endohedral non-metallic atom doping (remain nearly unchanged for N doping). The encapsulated non-metallic atoms are not covalently bound to the cage and, in accord with the experiments, they nearly keep atomic electronic configuration. Both electron-donating and electron-accepting ability of the cage are enhanced upon endohedral non-metallic atom doping such as endohedral metal atom doping.