The study of topological indices - graph invariants that can be used for describing and predicting physicochemical or pharmacological properties of organic compounds - is currently one of the most active research fields in chemical graph theory. In this paper we study the Schultz index and find a relation with the Wiener index of the armchair polyhex nanotubes TUV C(6)[2p; q]. An exact expressi...

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...

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...

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 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...

The effect of defect complexes on the stability, structural and electronic properties of single-walled carbon nanotubes and boron nitride nanotubes is investigated using the ab initio pseudopotential density functional method implemented in the Castep code. We found more substantial atomic relaxations in the zig-zag carbon nanotube than the armchair one. We find that the B(C)B(c) defect introdu...

Metallic single-walled carbon nanotubes have been proposed to be good one-dimensional conductors. However, the finite curvature of the graphene sheet that forms the nanotubes and the broken symmetry due to the local environment may modify their electronic properties. We used low-temperature atomically resolved scanning tunneling microscopy to investigate zigzag and armchair nanotubes, both thou...

Abstract: The Hosoya polynomial of a molecular graph G is defined as ∑ ⊆ = ) ( } , { ) , ( ) , ( G V v u v u d G H λ λ , where d(u,v) is the distance between vertices u and v. The first derivative of H(G,λ) at λ = 1 is equal to the Wiener index of G, defined as ∑ ⊆ = ) ( } , { ) , ( ) ( G V v u v u d G W . The second derivative of ) , ( 2 1 λ λ G H at λ = 1 is equal to the hyper-Wiener index, d...

We consider theoretically an armchair carbon nanotube (CNT) in the presence of an electric field and in contact with an s-wave superconductor. We show that the proximity effect opens up superconducting gaps in the CNT of different strengths for the exterior and interior branches of the two Dirac points. For strong proximity induced superconductivity the interior gap can be of the p-wave type, w...