Comparative NEXAFS examination of single‐wall carbon nanotubes produced by different methods

Three types of single‐wall carbon nanotubes (SWCNTs) have been comparatively studied using near C K‐edge X‐ray absorption fine structure (NEXAFS) spectroscopy. The samples have been produced by laser vaporization, chemical vapor deposition (CVD), and super growth methods and contained SWCNTs with the average diameter of 1.2, 2.4, and 4.0 nm, respectively. The π* resonance of the NEXAFS spectra of the samples showed four features slightly distinguished in the intensity and energy position. Quantum‐chemical calculations revealed that these features could be determined by unoccupied partial density of states of the core‐hole‐exited carbon atoms.