From isotope labeled CH3CN to N-2 inside single-walled carbon nanotubes

The observation of one-dimensional N-2 inside single-walled carbon nanotubes raises the questions, how are the N-2 molecules formed and how do they manage to make their way to this peculiar place? We have used N-15 and C-13 isotope labeled acetonitrile during the synthesis of single-walled carbon nanotubes to investigate this process. The isotope shifts of phonons and vibrons are observed by Raman spectroscopy and X-ray absorption. We identify the catalytic decomposition of acetonitrile as the initial step in the reaction pathway to single-walled carbon nanotubes containing encapsulated N-2.