Computational characterization of the HOMO-2 photoemission intensity oscillations in C60

We have calculated the photoionization cross section of the HOMO, HOMO-1 and HOMO-2 photoemission bands of C60 from threshold up to 250 eV of photon energy. The calculated HOMO-2/HOMO-1 intensity ratio is in excellent agreement with recent experimental data. The computational method uses a multicentric expansion of the scattering wave function and a density functional theory (DFT) Hamiltonian. Time dependent DFT calculations suggest that the oscillatory phenomenon is essentially of single particle nature. An interpretation of the experimental findings in terms of the σ–π symmetries of the ionized orbitals is provided.