High resolution X-ray absorption on metallicity selected C(60) peapods, single-, and double walled carbon nanotubes

We have investigated the C1s core level X-ray absorption of bulk samples of C(60)-peapods and double wall carbon nanotubes (DWNTs) derived from either metallic or semiconducting single-walled carbon nanotubes (SWNTs). The clear cut separation of the different species unveils their distinct electronic van Hove singularities (VHS). The core level spectra of peapods are a quantitative superpositon of the conduction band of nanotubes and unoccupied molecular orbitals of C(60). The outer shell metallicity selected DWNTs reveal changes in the pi* resonance due to the inner shell VHS.