عنوان مقاله [English]
A theoretical model for the normalized transversal polarizability of a single-walled carbon nanotube is presented within the framework of the quasi-static approximation. In this way, a single-walled carbon nanotube is modeled by an infinitesimally thin cylindrical shell of the πand σelectrons and electronic excitations of this shell is described by means of the two-dimensional two-fluid quantum hydrodynamic theory. General expression of polarizability of system is obtained, by solving Laplace and quantum hydrodynamic equations with appropriate boundary conditions. By using the polarizability formula, the extinction spectrum of system is investigated which is in fair agreement with the previous results. Therefore, the approach based on the quasi-static approximation may be considered as a simple and robust formalism for the investigation of optical properties of carbon nanotubes.