Electronic Structures and Nonlinear Optical Properties of Highly Deformed Halofullerenes C3v C60F18 and D3d C60Cl30

Electronic structures and nonlinear optical properties of two highly deformed halofullerenes C-3v C60F18 and D-3d C60Cl30 have been systematically studied by means of density functional theory. The large energy gaps (3.62 and 2.61 eV) between the highest occupied and lowest unoccupied molecular orbitals (HOMOs and LUMOs) and the strong aromatic character (with nucleus-independent chemical shifts varying from -15.08 to -23.71 ppm) of C60F18 and C60Cl30 indicate their high stabilities. Further investigations of electronic property show that C60F18 and C60Cl30 could be excellent electron acceptors for potential photonic/photovoltaic applications in consequence of their large vertical electron affinities. The density of states and frontier molecular orbitals are also calculated, which present that HOMOs and LUMOs are mainly distributed in the tortoise shell subunit of C60F18 and the aromatic [18] trannulene ring of C60Cl30, and the influence from halogen atoms is secondary. In addition, the static linear polarizability and second-order hyperpolarizability of C60F18 and C60Cl30 are calculated using finite-field approach. The values of and for C60F18 and C60Cl30 molecules are significantly larger than those of C-60 because of their lower symmetric structures and high delocalization of pi electrons. (C) 2010 Wiley Periodicals, Inc. J Comput Chem 31: 2650-2657, 2010