Optical properties of carbon compounds near the K-edge

XANES region optical properties of the following four carbon compounds with π* molecular orbitals are investigated: C60, C70, a carbon nanotube, and graphite. To determine the real and imaginary parts of the optical constants of the above, the atomic-scattering factors of these compounds near the K-edge of carbon are calculated using observed XANES spectra data and the Hartree-Slater method. Anomalous dispersions are observed in the real and imaginary parts of the optical constants near the K-edge. Each of the compounds are found to possess refractive indices that vary sharply with photon energy. In fact, we provide optical data for these four compounds that has not previously been given anywhere else.