Computational characterization of the HOMO-2 photoemission intensity oscillations in C-60

We have calculated the photoionization cross section of the HOMO, HOMO-1 and HOMO-2 photoemission bands of C-60 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 sigma-pi symmetries of the ionized orbitals is provided. (C) 2011 Elsevier B.V. All rights reserved.