Abstract
Computer simulation of the interaction of diatomic A2 molecules (A = C, Si, N, P, O, S) with a super-small single-walled carbon nanotube (SWCNT) sensor was performed. The nonlocal density functional B3LYP / 3-21G (ORCA package) was used to study the supratomical nanosystem. For all molecules, it has been shown that the most preferable orientation of their axis is perpendicular to the outer surface of the SWCNT. Significant differences were found in the adsorption of molecules of group IV a (C, Si), group V a (N, P) and group VI a (O, S) of the periodic table of elements. The calculation showed that the chemisorption of the molecules C2 and Si is characterized by binding energies of 2.91 eV, 1.51 eV and equilibrium distances from the SWCNT surface of 1.39 A and 2.91 A, respectively. For a C2 molecule, a covalent bond with a pair of carbon atoms is preferred, while for a Si2 molecule, a covalent bond with one of the carbon atoms is more stable. In turn, for the N2, P2, O2, S2 molecules, it is preferable to be located in the center of carbon sextet at a distance from the surface of the SWCNT: 3.00 A, 3.17 A, 2.66 A, 2.96 A with binding energy: 0.15 eV, 0.27 eV, 0.39 eV, 0.52 eV, respectively.