Boron nanotubes and their properties: semiempirical investigation

Abstract
The problem of formation possibility nanotubular structures is actively discussed now. We considered the fragments of single-wall boron nanotubes (n, n) (n=4, 5, 6, 9, 11, 12). Calculations were carried out by IB-CCC method [Litinskii A.O., et al., Journal of physical chemistry - 1995 - V. 69., N° 1., P. 189. (In Russian)]. The analysis of band-gap showed that all of them are semiconductors. Energy of deformation decreases with increase of the diameter of B-tubes (n, n). We considered the B-nanotubes (n, 0) (n=4, 5, 6, 8, 12). In this case deformation energy is increases with increase of the diameter of tubes (n, 0). Calculations of boron tube (6, 6) which contained various defects of structure were obtained by the semiempirical MNDO scheme. We research substitution imperfection of B atom by atom C, ions C⁺, C^-. We found out substitution energy of defects and its energy level. We studied the B-tube with atomic vacancy and determined the energy of defect activation and the relative portion of vacancies.At the moment active search of new surface structures capable of effective adsorption of different gases is being carried out. We have investigated an binding opportunity between the H, F, O, Cl atoms and the outer surface of B-nanotube (6,6) and have studied the mechanism of this process. The calculations are carried out with the use of quantum chemical MNDO scheme. Regular hydrogenation of boron nanotubes was investigated. We can confirm that generation of gas-phase hydrogen composite materials based on boron nanotube is possible.