The role of environmental effects on the optical transition energies and radial breathing mode frequency of single wall carbon nanotubes

In this paper we discuss the environmental effects on the radial breathing mode (RBM) spectra of Single Wall Carbon Nanotubes (SWNTs). We have shown that the environmental effect on the radial breathing mode frequencies can be explained by Van-der-Waals interactions. We here explore these interactions concerning its (n, m) dependence and curvature effects. Furthermore, most of the optical transition energies available in the literature (E-ii(Lit.)) are downshifted with respect to the optical transition energies for super-growth (S.G.) tubes (E-ii(S.G.)). The effect on transition energies can be understood considering the effect of the dielectric constant of the medium in the excitonic optical transition. (C) 2008 WILEY-VCH Veriag GmbH & Co. KGaA, Weinheim