Theoretical study on the structures, properties and spectroscopies of fullerene derivatives C 66X 4 (X = H, F, Cl)

Abstract

The geometrical structures, electronic properties, and spectroscopies of non-IPR (isolated pentagon rule) fullerene C 66 and its derivatives C 66X 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 C 66 cages can form new non-IPR fullerenes such as C 66X 4, where the molecule C 66X 4 with C 2 v 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 66X 4 are also presented.