Core-level photoemission from graphite

Core-level photoemission spectra of graphite have been measured at very hig h resolution. The C 1s level is found to have a lifetime width with an uppe r limit of 165 +/- 15 meV, which is considerably narrower than preciously r eported. The width is still substantially larger than that observed for car bon ionic states in small molecules. We argue that the additional broadenin g in the solid state is not due to a surface core-level shift or initial-st ate band formation, but may be due to unresolved final-state phonon broaden ing.