Narrow photoemission lines from graphite valence states

Valence-band photoelectron angular distributions, measured in the photon energy range $20-150\mathrm{eV},$ are obtained from crystalline graphite overlayers prepared by heating SiC(0001) and from a graphite natural single crystal. The dispersion of the valence bands for the overlayers agrees well with that of the single crystal. The valence electrons have binding energies, which agree with LDA calculations if the calculated binding energies are multiplied by a factor of 1.13. The upper $\sigma$ state at $\Gamma$ and states near the Fermi level at the zone corners give quite narrow emission lines. Since the widths are on par with that of the C $1s$ level the lines are of interest as an alternative to the core line when graphite is used as substrate for adsorption or absorption studies.