Adiabatic and vertical ionization potentials (IPs) of single-walled carbon nanotubes (SWCNTs) as a
function of length were determined by using density functional theory. The correlation between periodic
oscillations of SWCNTs local aromaticity and the values of IPs was founded. In the case of short SWCNTs
an appreciable gap between vertical and adiabatic IPs was observed, whereas for longer nanotubes these
values are almost equal. It was also established that the HOMO electron density distribution in neutral