Theoretical Study on the Structure and Spectral Properties of Several Classical C84 Isomers and Their Newly Synthesized Derivatives

The ground-state electronic/geometrical structures of the three classical isomers C s (15)-C84, C 2(13)-C84, and C 2(8)-C84 as well as the corresponding embedded derivatives U@C s (15)-C84, YCN@C 2(13)-C84, and U@C 2(8)-C84 have been calculated at the density functional theory (DFT) level. Then, the isomers of C84 were theoretically identified by X-ray photoelectron spectroscopy (XPS) and near X-ray absorption fine-structure spectroscopy (NEXAFS). The spectral components of total spectra for carbon atoms in various local environments have been investigated. The ultraviolet–visible (UV–vis) absorption spectroscopies of U@C s (15)-C84, YCN@C 2(13)-C84, and U@C 2(8)-C84 have also been performed utilizing time-dependent (TD) DFT calculations. The UV–vis spectra are in good agreement with the experimental results. These spectra provide an effective method for the identification of isomers. The results of this study can offer useful data for further experimental and theoretical studies using X-ray and UV–vis spectroscopy methods on freshly synthesized fullerene isomers and their derivatives.