Single-particle excitation spectra of C60 molecules and monolayers

In this paper, we present calculations of single-particle excitation spectra of neutral and three-electron-doped Hubbard C60 molecules and monolayers from large-scale quantum Monte Carlo simulations and cluster perturbation theory. By a comparison with experimental photoemission, inverse photoemission, and angle-resolved photoemission data, we estimate the intermolecular hopping integrals and the C60 molecular orientation angle, finding agreement with recent x-ray photoelectron diffraction experiments. Our results demonstrate that a simple effective Hubbard model, with intermediate coupling U=4t, provides a reasonable basis for modeling the properties of C60 compounds.