Signature of the orbital character in the electronic band structure of C₆₀ through photoemission experiments

Using Angle-Resolved Photoemission Spectroscopy (ARPES), we have observed strong photon-dependent oscillations of C₆₀ valence band clusters’ intensity. These oscillations have been reported in the literature and are related to the spherical geometry of the C₆₀ molecule, where photoelectron waves emanating from each carbon atom in the molecule experience interference inside the molecule. Here, we report the analysis of such oscillations coming from a highly ordered C₆₀ thin film crystal. Using Fourier transform analysis, we show that the frequency and phase of these oscillations are intimately related to the orbital character of the different C₆₀ valence band clusters. These results open avenues to probe the orbital character of the band structure of other fullerene or large molecule thin films.