Photoemission studies of graphite high-energy conduction-band and valence-band states using soft-x-ray synchrotron radiation excitation

Photoemission spectra of the valence band of single-crystal graphite were measured using synchrotron radiation in the energy range 33-200 eV. For =122 eV, good agreement was found with the calculated density of states since the matrix elements for the p-like and s-like states are nearly the same. Using constant-initial-state spectroscopy, we have found that, for 90 eV, the transition cross sections are mainly determined by the atomic character of the initial states.