A theoretical analysis of the photoabsorption spectra of big single-shell spherical fullerenes

Using a Hückel model of the one-electron structure and the semiclassical random phase approximation to account for electron screening, we have performed a systematic analysis of the photoabsorption spectra of single-shell spherical fullerenes from the icosahedral family C60n2. We have paid special attention to the emergence of macroscopic features in the larger fullerenes by going up to n=10. We find that the electron screening effects tend to vanish with increasing fullerene size, the spectra reaching an asymptotic stable form. These results differ markedly from those derived with a representation of the electron motion as a 2D spherical electron gas.