Electronic angular momentum effects in the photophysical behavior of fullerenes

The intensity of the electronic origin in the emission spectrum of C₇₀ exhibits a strong solvent sensitivity. The intensity of this peak increases relative to the vibronic features as the dielectric constant of the solvent increases. This solvent dependence is explained by an extension of Platt's Perimeter Free Electron Orbital model. The fullerenes, in particular C₆₀ and C₇₀, possess a nearly spherical symmetry that gives rise to the presence of significant electronic orbital angular momentum. The unexpected spectral sensitivity is shown to arise from quenching of the electronic angular momentum by the solvent environment.