* Department of Physics, R.B.S. College, Chandi Dhenuki, Vaishali, BIHAR, INDIA.
** Department of Physics, L.S. College, Muzaffarpur, BIHAR, INDIA.
*** Department of Physics, Z.A. Islamia College, Siwan, BIHAR, INDIA.
University Department of Physics, B.R.A. Bihar University, Muzaffarpur, BIHAR, INDIA.
We have studied electronic and transport properties of carbon nanotubes using tight-binding models. The depolarization effect shifts the excitation energy to higher energy side and suppresses intensity of the absorption peaks. As a result excitation energy becomes closer to that associated with that of the second gap for parallel polarization. The intensity of the absorption peaks is weakly dependent on the Coulomb interaction and the tube diameter through the cut off energy. The excitation absorption for perpendicular light is systematically studied with emphasis on the depolarization effect and dependence on the strength of the Coulomb interaction and the tube diameter.
Electronic and transport properties, Carbon nanotubes, Depolarization effec
