A comprehensive density functional theory study on molecular structures of (5, 5) carbon nanotube doped with B, N, Al, Si, P, Co, and Ni

Abstract

Armchair single-walled carbon nanotubes (SWNTs), which were doped with B, N, Al, Si, P, Co, and Ni, have been studied using computational simulations based on density functional theory (DFT). The topological analysis and the electron localization function show that the nature of the interaction between carbon atoms and the dopant X atoms is not purely covalent or an ionic. In order to gain a deeper understanding of the interaction between X atoms and C atoms, calculations of natural bond orbital (NBO) analysis, bond order analysis, atomic charge analysis, and electrostatic potential (ESP) on the van der Waals (vdW) surfaces of molecules are required. The Natural population analysis (NPA), Hirshfeld and atomic dipole moment corrected Hirshfeld (ADCH) atomic charges and molecular electrostatic potential maps on vdW surfaces of C79H20Xs show that ESP values are in good agreement with ADCH values. The calculations of The Laplacian bond order (LBO), Mayer bond order (MBO) and Fuzzy bond order (FBO) illustrate that LBO has a strong correlation with the bond length. In addition, the calculations show that Fermi energies of the pristine C (5, 5) carbon nanotubes (CNTs) and all doped CNTs are equal to the energies of their highest occupied molecular orbital (HOMO). This work presents a comparison about the bonding characteristic between the doped atoms (X) and carbon atoms.