The Al-Doped Carbon Nanotubes: A DFT Study

Abstract

NMR parameters consisting of isotropic and anisotropic chemical shielding parameters have been calculated based on density functional theory (DFT) to investigate the properties of the electronic structures of the aluminum doped (Al-doped) carbon nanotubes (CNTs). The structures are allowed to relax by performing all atomic optimization. Then the chemical shielding (CS) tensors are calculated for 13C and 27Al nuclei in the Al-doped forms and also pristine models of the (4,4) armchair and (6,0) zigzag CNTs. The calculated CS tensors in the optimized structures are converted to chemical-shielding isotropic (CSI) and chemical-shielding anisotropic (CSA) parameters. In comparison to the pristine model, the CSI parameters of the C atoms around the Al-doped are significantly influenced by the doping process. Density functional theory (DFT) calculations are performed using Gaussian 98 suite of programs.