LAUSR

Abstract The recently reported experimental optical spectra of double-walled carbon nanotubes exhibit more peaks than it could be expected based on the layers alone. The appearance of excess peaks has been attributed to the interlayer interaction. In order to elucidate the origin of the excess peaks, we perform calculations of the optical absorption of a particular nanotube using the recursion method with non-orthogonal tight-binding basis functions. Our study shows that the interlayer interaction can give rise to major changes in the electronic structure of this nanotube, manifesting themselves with shifts of the optical transitions and appearance of new optical transitions. The derived absorption spectrum is found to be in excellent agreement with the available experimental data, which justifies the use of the proposed approach for double-walled carbon nanotubes.