The nature of enhanced linear and nonlinear optical effects in fullerene solutions

The “blue” emission from fullerene C 60 and its derivatives in frozen toluene solution is discovered and analyzed in the framework of the electromagnetic theory of enhanced optical effects. It is shown that the emission, combining enhanced spectra of Raman scattering and one-photon luminescence, is due to clustering of fullerene molecules in solution. Photoexcitation of charge-transfer excitons in clusters provides the polarization required for the enhancement. A direct relationship is established between the observed phenomenon and nonlinear optical properties of the medium. Empirical and computational tests are proposed to select matrices with various nonlinear optical properties.