Quantum size effects in the polarizability of carbon fullerenes.

We investigate the size-dependent dielectric response of carbon fullerenes with up to 3840 atoms in the framework of the linear response theory. Our results suggest a significant polarizability enhancement due to quantum size effects with respect to classical or semiclassical calculations. The accuracy of our results, based on a parametrized Hamiltonian, is verified by ab initio time dependent density functional calculations for smaller fullerenes. Our findings underline the importance of quantum effects in the electronic response of nano- and mesoscopic systems.