Ab initiostudy of the optical absorption and wave-vector-dependent dielectric response of graphite

摘要: We performed ab initio calculations of the optical absorption spectrum and wave-vector-dependent dielectric energy-loss functions graphite in framework random-phase approximation. In spectrum, most prominent peaks were analyzed terms interband transitions from specific regions Brillouin zone. The inclusion crystal local-field effects (LFE) response had an important influence on for light polarization parallel to c axis. calculated electron spectra, even without LFE, very good agreement with existing momentumdependent experiments concerning peak positions two valence-electron plasmons. Important aspects line shape anisotropy function at large momentum transfer q also well described: splitting total sp +sd plasmon appearance originating transitions. Finally, role interlayer interaction was studied, particular regard its effect c, position higher-frequency p +s plasmon.