  Nonlinear optical properties of extracted higher fullerenes - C70, C76, C78,
and C84 - are theoretically investigated. Magnitudes of off-resonant
third-harmonic-generation are calculated by the intermediate exciton theory. We
find that optical nonlinearities of higher fullerenes are a few times larger
than those of C60. The magnitudes of nonlinearity tend to increase as the
optical gap decreases in higher fullerenes.
