Carbon 1 s near-edge-absorption fine structure in graphite

Abstract

High-resolution ${\mathit{p}}_{\mathit{z}}$- and ${\mathit{p}}_{\mathit{x},}$y-projected fine structure for the 1s carbon core level in graphite are compared with symmetry-projected calculations. A very sharp transition occurs about 7.6 eV above the Fermi energy in the ${\mathit{p}}_{\mathit{x},}$y results, agreeing closely with the nondispersive ${\mathrm{\ensuremath{\sigma}}}^{\mathrm{*}}$ band. An additional feature near 8.5 eV above the Fermi energy may be due to the ${\mathrm{\ensuremath{\Gamma}}}_{2}^{\mathrm{\ensuremath{-}}}$ branch of the free-electron-like interlayer states. With a modest excitonic distortion, the ${\mathit{p}}_{\mathit{z}}$ results agree closely with the expected ${\mathrm{\ensuremath{\pi}}}^{\mathrm{*}}$ band.