Angular-resolved Photoelectron Spectroscopy of Superatom Orbitals of Fullerenes

Photoelectron angular distributions from both C-60 and C-70 were recorded for low laser intensity femtosecond and picosecond pulses. Rich structure is seen for electron kinetic energies that lie below the photon energy. Strong, broad peaks are observed for photoelectron energies corresponding to single-photon ionization of so-called superatom molecular orbitals (SAMOs). The very simple angular distributions measured for these peaks, the close similarity of the spectra observed from C-60 and C-70, and the comparison with time-dependent density functional theory provide strong support for the SAMO hypothesis.