Structure of singlewall carbon nanotubes: neutron powder diffraction and simulations.

We report on the calculation of diffraction spectra for finite size cristalline bundles of singlewall carbon nanotubes (SWNT). We show that the general profile of the spectra is sensitive to the following structural parameters of the sample: tubes symmetry, tubes diameter and polydispersity, and ropes diameter. We find a good agreement between the calculated and the experimental diffraction spectra.