Excitation spectra of free fullerene clusters

In this work we study the single electron emission from fullerene clusters upon the impact of low-energy electrons. The calculations of the quantum ground states of the fullerene are performed within the Hartree–Fock and the jellium shell model. The interaction between the incoming projectile and knocked out electrons is described on the basis of random phase approximation with exchange, which leads to the concept of screening of the inter-electronic interaction. We compare the results of the calculations with available experimental data for the ionization of C60 by electron impact and show that neglect of polarization leads to results at variance with experimental finding.