Theoretical Study Of The Absorption Of Copper On (5,5) Armchair Single Carbon Nanotube And With Surface Defect

Single-walled carbon nanotubes (SWNT), which were first discovered by Iijima, especially, SWNT modified by some tradional atoms significanly have attracted intense interest because of their novel one-dimensional structure, superb mechanical and electronic properties in recent years.In this thesis, theoretical study of the absorption of copper on the perfect and existing defects (5, 5) armchair single-walled carbon nanotubes have been investigated by using a first-principle based upon the Density Functional Theory. All calculations are used the DMol~3 package of Materials Studio 4.0. The study mostly included three aspects.(1) The absorption of copper atoms on the armchair (5, 5) single wall carbon nanotube has been investigated by the density functional theory density functional theory because the materials of carbon nanotube modified copper become a field of growing interest. It is shown that the absorption on the outside is energetically preferred than inside, Moreover, adsorbed copper atom on the top of carbon is the most stable among the other outside site. At the same time, the character of the bond on the top of carbon between copper and SWNT has been detailed. The absorption behavior belongs to chemical absorption and based on the analysis of frontier orbital it is shown that the newσbond is mainly due to the interaction of 4s valence state of copper and couplingσ-πbond of SWNT. Furthermore, the calculated electron density of two representative adsorption positions show that electron clouds overlap more on the top of carbon adsorbed copper atom. Above all, copper and carbon atoms can form chemical bond in a sense.(2) The absorption of copper atoms on single wall carbon nanotubes (SWNTs) embracing two representative defects was studied by the density functional theory, It is found that the absorption energy on 5-1DB defects and on heptagonal carbon ring of Stone-Wales type defective site are significantly larger than other sites on SWNTs, suggesting selective absorption of copper on these defects. Importantly, by analyzing frontier orbitals of the complexion of copper and SWNTs, we have found 3d orbital of copper plays a key role in the formation of new bond.(3) We study absorption behavior of seven copper atoms on singe wall carbon nanotubes. It is shown that the absorption behavior is different from Cu monomers, For Cu dimers in the most stable configuration, the Cu-Cu bond is on the brige of C - C bond positions, even Cu-Cu dimers upright the plane of C - C bond, with an Cu-Cu distance of 0.2276 nm. With increase of copper atoms (>3) , the configuration of absorption all make up to three layers sheet copper atoms ,and the thickness of film is around 0.75 nm.Moreover, the structure and properties of gadolinium nitrate has been investigated, which may heplp to understand the explosion mechanism of the compound from porous silicon and gadolinium nitrate.