Qing-Bo Yan, Qing-Rong Zheng, Gang Su*

College of Physical Sciences, Graduate University of Chinese Academy of Sciences, P.O. Box 4588, Beijing 100049, China

Received 18 November 2006; accepted 28 April 2007
Available online 18 May 2007

Abstract:

   The geometrical structures, electronic properties, and spectroscopies of non-IPR (isolated pentagon rule) fullerene C ₆₆ and its derivatives C ₆₆ X ₄ (X = H, F, Cl) have been studied by the first-principle calculations based on the density functional theory. By searching through all 4478 isomers of C ₆₆ , the ground state of C ₆₆ is observed to bear C _s symmetry and have two pairs of fusion pentagons. It is found that the addition of H, F, Cl atoms to the pentagon–pentagon fusion vertex of C₆₆ cages can form new non-IPR fullerenes such as C₆₆ X₄ , where the molecule C₆₆ X ₄ with C _2v symmetry are uncovered to be the most stable among others. The Mulliken charge populations, gap energies between the highest-occupied molecular orbital (HOMO) and the lowest-unoccupied molecular orbital (LUMO), and density of states of these unconventional fullerenes are calculated, showing that different atoms added to non-IPR C ₆₆ cages will alter the charge populations remarkably; the chemical deriving could affect the electronic structures distinctly, and improve the stability of the fullerenes. The calculated results of IR, Raman, NMR spectra of C ₆₆ X ₄ are also presented.