Adsorption of CO2 on the surface of Single-wall zigzag (5,0) and armchair (4,4) carbon nanotubes (SWCNTs) were studied through using density functional theory (DFT) calculations. Optimizations of geometric were performed at the B3PW91 level of 6-311++G** method standard basis set using GAUSSIAN 03 package of program [1]. Structural models were optimized and adsorption energies, band gap, charge...

The electronic structures of carbon nanotubes doped with oxygen dimers are studied using the ab initio pseudopotential density functional method. The fundamental energy gap of zigzag semiconducting nanotubes exhibits a strong dependence on both the concentration and configuration of oxygen-dimer defects that substitute for carbon atoms in the tubes and on the tube chiral index. For a certain ty...

In this paper, (10, 0) zigzag nanotubes and (6, 6) armchair nanotubes are considered to investigate the effects of randomly distributed vacancy defects on mechanical behaviors of single-walled carbon nanotubes. A spatial Poisson point process is employed to randomly locate vacancy defects on nanotubes. Atomistic simulations indicate that the presence of vacancy defects result in reducing nanotu...

The symmetry properties of the single-walled BC(2)N nanotubes were investigated. All the BC(2)N nanotubes possess nonsymmorphic line groups. In contrast with the carbon and boron nitride nanotubes, armchair and zigzag BC(2)N nanotubes belong to different line groups, depending on the index n (even or odd) and the vector chosen. The number of Raman- active phonon modes is almost twice that of th...

Using nonequilibrium molecular dynamics simulations and nonequilibrium Green's function method, we investigate the thermoelectric properties of a series of zigzag and chiral carbon nanotubes which exhibit interesting diameter and chirality dependence. Our calculated results indicate that these carbon nanotubes could have higher ZT values at appropriate carrier concentration and operating temper...

We propose a catalytic growth mechanism of single-wall carbon nanotubes based on density functional total energy calculations. Our results indicate nanotubes with an “armchair” edge to be energetically favored over “zigzag” nanotubes. We also suggest that highly mobile Ni catalyst atoms adsorb at the growing edge of the nanotube, where they catalyze the continuing assembly of hexagons from carb...

Spin-polarized density functional theory is used to investigate hydrogen-induced magnetism in single-walled carbon nanotubes SWNTs . Hydrogen trapped at a carbon vacancy can trigger delocalized electron spin polarization on semiconducting zigzag SWNTs. Hydrogen pinned by a carbon adatom on the surface of the SWNT can induce spin polarization localized at the carbon adatom, independent of the di...

The extinction and orientational dependence of electron diffraction from single-walled carbon nanotubes have been observed experimentally and investigated in detail theoretically using both algebraic analysis and numerical simulations. Electron diffraction from only achiral carbon nanotubes of zigzag or armchair structure shows observable orientational dependence and extinction of certain layer...

Molecular dynamics simulations are carried out to study the reorientation of single wall carbon nanotubes in a polyethylene matrix under the influence of a 25 T magnetic field. The simulations are based on a variant of velocity Verlet algorithm, which relaxes the Larmor time-step restriction while preserving second-order accuracy. Simulations reveal that the unfolding and reorganization of the ...

We study the electronic structure of the junctions between a single graphene layer and carbon nanotubes, using a tight-binding model and the continuum theory based on Dirac fermion fields. The latter provides a unified description of different lattice structures with curvature, which is always localized at six heptagonal carbon rings around each junction. When these are evenly spaced, we find t...