The chemical bonding and electronic structures of carbon nanotubes were investigated using high-resolution C K-edge near-edge X-ray absorption fine structure methods monitoring both the total electron and fluorescence yields. The measurements probed the densities of state above the Fermi level. Newly-observed peaks at 284.5 and 290.5eV were attributed to rolling of the carbon layers and to defects in the nanotubes, respectively. The high-resolution C K-edge spectra of carbon nanotubes were of fundamental interest with regard to the properties and composition of carbon nanotube.

Near-Edge X-Ray Absorption Fine Structure Study of Helicity and Defects in Carbon Nanotubes. Y.H.Tang, T.K.Sham, Y.F.Hu, C.S.Lee, S.T.Lee: Chemical Physics Letters, 2002, 366[5-6], 636-41