Stabilities, aromaticity, infrared spectra, and optical properties of exohedral fullerene derivatives C_(76)X_(18)(X=H, F, Cl, and Br)

摘要

Density functional study is performed on the stabilities, aromaticity, infrared spectra, and optical properties of exohedral fullerene derivatives C_(76)X_(18)(X=H, F, Cl, and Br). The bond dissociation energy and energy gap between HOMO and LUMO of C76H18 are larger than those of the isolated C_(76)F_(18) and C_(76)Cl_(18), indicating the possibility for synthesising C76H18 from the viewpoint of thermodynamics and kinetics. C_(76)X_(18)(X=H, F, Cl, and Br) show strong aromaticity, suggesting their stabilities are correlative with the conjugation. The tensors of static linear polarisabilities, mean static linear polarisabilities, polarisability anisotropy, and first-order hyperpolarisabilities of C_(76)X_(18)(X=F, Cl, and Br) increase as X goes from F to Br. We rationalise the nonlinear properties by studying the low-energy optical absorption band obtained by employing time-dependent density functional theory.