Ab Initio Studies of Vacancy-Defected Fullerenes and Single-Walled Carbon Nanotubes

The structures, stabilities, and electronic properties of the single-vacancy-defected fullerenes, C-60 and C-70, and the single- and double-vacancy-defected single-walled carbon nanotubes (SWCNTs) were studied within density functional theory. The isomerization barriers for the single-vacancy-defected C,, on the triplet potential energy surface (PES) are lower than those on the singlet PES. The symmetric double-vacancy-defected (10,0) SWCNT is the most stable one among the models investigated. According to the analyses of frontier molecular orbitals (FMOs), nature bond orbitals, and local density of states, introduction of vacancy on the SWCNT decreases the band gap of semiconducting SWCNT, increases the band gap of conducting SWCNT, destructs the pi conjugation of the FMOs, and gives rise to enhanced chemical activity. (C) 2009 Wiley Periodicals, Inc. Int J Quantum Chem 109: 3441-3456, 2009