Adsorption of N2, O2, CO, and CO2 on open ends and surface of single wall carbon nano-tubes: A computational nuclear magnetic resonance and nuclear quadrupole resonance study

The critical conductivity regime of carbon nanotube strongly depends on the its chirality and symmetry after the adsorption of various gas molecules. a) Nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) parameters, including isotropic and anisotropic chemical shielding parameters, were calculated to study the adsorption of N-2, O-2, CO, and CO2 on pristine SWCNTs by DFT technique. b) Bond lengths, bond angles, tip diameters, dipole moments, energy levels, highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), band gaps, and electronic chemical potential (mu) for the lowest energy that is derived to estimate the structural stability of the composites, were also investigated for the sensitivity of the composites' electronic properties for application in gas sensors. c) It is more pronounced that molecule-induced modification of the density of states close to the Fermi level, charge transfer and gas-induced charge fluctuation might significantly affects the transport properties of nanotubes. d) The adsorption properties and NMR and NQR of zigzag (5, 0) and armchair (4, 4) SWCNTs with the optimal lengths of 7.1 angstrom and 8.6 angstrom, respectively, as a gas sensor and the optimized adsorption rates were calculated. (C) 2016 Elsevier B.V. All rights reserved.