The IPsa of the SWCNTs were determined by applying the following procedures. The total energies of a neutral nanotube and a +1 charge radical cation (SWCNT radical dot+) of the same tube were calculated at the B3LYP/SVP level. The ionization energy was then obtained by subtracting the total energy of the neutral nanotube from the energy of the +1 charge nanotube radical cation
In order to obtain IPsv, we calculated the total energies of the ionic states of each SWCNT, using the optimized geometry of the neutral system, then we subtracted the total energy of the neutral nanotube from the energy of the radical cation of SWCNT obtained at the geometry of neutral