One-electron states and interband optical absorption in single-wall carbon nanotubes

Explicit expressions for the wavefunctions and dispersion equation for the band π-electrons in single-wall carbon nanotubes are obtained within the method of zero-range potentials. They are then used to investigate the absorption spectrum of polarized light caused by direct interband transitions in isolated nanotubes. It is shown that, at least, under the above approximations, circular dichroism is absent in chiral nanotubes for a light wave propagating along the tube axis. The results obtained are compared with those calculated in a similar way for a graphite plane