First-Principle Calculations For The Adsorption Of Rare Gas Atoms On C/BN Nanotube

In this thesis, the characteristics of carbon nanotubes (CNT) and boron nitride nanotubes (BNNT) adsorbing rare gas atoms are calculated based on first-principles theory, to four adsorption sites of outer walls of carbon nanotubes. The absorption and electrical properties of carbon nanotubes doped with boron and nitrgen atoms are analysised. The main conclusions of calculations are listed as follows:Base on the LD A method, the calculations show the adsorption of rare gas atoms on CNT are exothermic. Neon atom has the strongest adsorption, but Xe the weakest.Base on the calculation with LDA method, it shows that the boron atom doped in CNT has a positive affect to adsorb rare gas, but the nitrogen atom a negative affect.The rusults of calculation with the GGA metohod show that the adsorption of neon atom is the strongest and that of helium atom the weakest. And the calculated adsorption energies with GGA method are lower than those with LDA method.The results with DFT-D2 method show that the adsorption of neon atom is the strongest, and that of xenon atom is the second.The results with LDA method show that the adsorption energy of xenon atom on boron nitride nanotubes (BNNT) is positive and endothermic, but those of others are negative and exothermic. It implies that xenon can be separated from other rare gas by BNNT. The sequence of the adsorption energies on every adsorbing site of BNNT is EAr<ENe<EKr<EHe<EXe.