Unusual physical properties of single-wall carbon nanotubes have started a search for similar tubular structures of other elements. In this paper, we present a theoretical analysis of single-wall nanotubes of silicon and group-III-V compounds. Starting from precursor graphenelike structures we investigated the stability, energetics, and electronic structure of zigzag and armchair tubes using th...

We report optical properties of the smallest single-walled carbon nanotubes (SWNTs) with a diameter of only 3 A. These ultrasmall SWNTs are fabricated in the elliptical nanochannels of an AlPO-11 (AEL) single crystal. Polarized and resonant Raman scattering unambiguously revealed that these 0.3 nm SWNTs are of (2,2) armchair symmetry. Interestingly, the (2,2) armchair tube has two metastable gr...

In this paper, we have used density functional perturbation theory (DFPT) and Pseudo-potential method to calculate the phonon spectrum, phonon density of states (DOS), specific heat capacity and mechanical properties of (5,5) armchair and (9,0) zigzag Single Wall Carbon Nanotubes (SWCNTs). Our calculations show that Young’s modulusfor (5,5) and (9,0) nanotubesare higher than 1TPa. We have also ...

magnesium oxide nanotubes of finite length are investigated by the density functional theory (dft) at the b3lyp/6-31g (d) level. the (6, 0) zigzag and (4, 4) armchair of mgo nanotubes were considered and nuclear magnetic resonance properties including isotropic and anisotropic chemical shielding parameters (csi and csa) were calculated for 25mg and 17o atoms of the optimized structures for the ...

We report the one-electron spectrum and eigenstates of infinite achiral chiral $(2m,m)$ carbon nanotubes found by using analytic solution to Schr\"odinger equation for tight-binding H\"uckel-type Hamiltonian. With help matching wave functions on interfaces between regions, where electrons have different site energies, we find compare transmission coefficients zigzag, armchair subjected action a...

The colors of suspended metallic colloidal particles are determined by their size-dependent plasma resonance, while those of semiconducting colloidal particles are determined by their size-dependent band gap. Here, we present a novel case for armchair carbon nanotubes, suspended in aqueous medium, for which the color depends on their size-dependent excitonic resonance, even though the individua...

Structurally uniform and chirality-pure single-wall carbon nanotubes are highly desired for both fundamental study and many of their technological applications, such as electronics, optoelectronics, and biomedical imaging. Considerable efforts have been invested in the synthesis of nanotubes with defined chiralities by tuning the growth recipes but the approach has only limited success. Recentl...

Chemical compounds and drugs are often modelled as graphs (for example, Polyhex Nanotubes and Dendrimer Nanostar) where each vertex represents an atom of molecule and covalent bounds between atoms are represented by edges between the corresponding vertices. This graph derived from a chemical compounds is often called its molecular graph and can be different structures. The edge Wiener index of ...

In this paper we demonstrate that soliton solutions, whose existence is well known in one-dimensional (1D) model anharmonic systems, can also exist in more complex systems such as carbon nanotubes (CNT). We investigate armchair and zigzag nanotubes and show that both can be simplified to anharmonic 1D lattice models with reduced internal degrees of freedom. Because of the differences in chirali...

the doping reaction of truncated boron nitride and carbon nanotubes with aluminium atom wastheoretically investigated. the am1, pm3, and pm6 semiempirical methods have been used toevaluate the thermochemistry of doping reactions of single walled boron nitride nanotubes andcarbon nanotubes. the enthalpy changes, gibbs free energy changes, and entropy changes of studieddoping reactions were evalu...