Relationship between the Auger line shape and the electronic properties of graphite

The experimental carbon Auger line shape for graphite has been obtained, corrected for the effects of the secondary-electron background and extrinsic losses, and placed on an absolute energy scale through the use of photoelectron measurements. The resulting line shape is compared to a model which consists of the self-convolution of the graphite one-electron density of states including atomic values for the symmetry-determined Auger matrix elements. A poor comparison results from this simple model which is considerably improved by the inclusion of dynamic initial-state screening effects. Further improvement results from accounting for final-state hole-hole interactions. The final state is characterized by effective hole-hole interaction energies of 2.2 eV corresponding to two holes in the {σ} band, 1.5 eV for one hole in the {σ} and one in the {π} band, and 0.6 eV for both holes in the {π} band. The remaining discrepancies in our model comparison are suggested to be due to a plasmon emission intrinsically coupled to the Auger final state.