The Study Of Single-walled Carbon Nano-cone And The Calculation Of Fullerenes And Their Derivatives Properties

The geometric and electronic properties of the single wall carbon nanohorns (Horn1-Horn5), metal-substituted fullerene C₅₉Sm and exohedral fullerenes C₆₀Sm, the nonclassical four-membered ring fullerene (4-Me-C₆H₄)₂-C₆₂, H₂-C₆₂, and F₂-C₆₂ are studied using the density functional theory.The geometric study of the single wall carbon nanohorns shows that there are five possible geometries according to the number of pentagons. Horn4 and Horn5, which contains four and five pentagons, respectively, have the similar structural compared with the experimental result, the C-C bonds which belong to the pentagons are all single, while the ones which connect the pentagons to the horns are all double. The comparison of the binding energies and electronic structures shows that Horn5 is the ground state geometry and has an open shell structure, while Horn4 has a tiny smaller binding energy and close shell structure.The geometric optimization of C₅₉Sm and C₆₀Sm shows that the replacement of a C atom with a Sm in C₆₀ yields a stable substitutionally doped fullerene C₅₉Sm, and among the five possible optimized geometries for C₆₀Sm, the most favorable exohedral sites are above the center of a hexagon and a pentagon ring. The calculations for electronic structures show that the magnetic moment of Sm is preserved for all the stable structures as tiny hybridization takes place between the orbitals of the Sm atom and those of their neighboring carbons. Because of the small energy gaps and the half occupation of the highest occupied molecular orbitals, all the stable C₆₀Sm isomers are inferred to be conductors.The computational results of C₆₂ show that, the frontier orbitals of C₆₂, particularly the highest occupied molecular orbital, are localized mainly around the four-membered ring. High stability is predict for (4-Me-C₆H₄)₂-C₆₂ due to its much lager energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital, compared with that of C₆₂. The frontier orbitals theory is used to study the possibility of synthesizing H₂-C₆₂ and F₂-C₆₂ in which H₂ and F₂ are used to replace the (4-Me-C₆H₄)₂ in (4-Me-C₆H₄)₂-C₆₂, the results show that F₂-C₆₂ might be much stable and...