“…In particular, the X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy were intensively employed in previous researches to identify fullerene isomers and their derivatives, such as C 34 , 31 C 48 N 12 , 32 C 58 N 2 , 33 C 76 , 24 C 78 , 23 C 82 , 34 two I h -symmetry-breaking C 60 isomers and their chlorinated species. 35 XPS provides the information of core orbitals, corresponding to the ionization of core electrons; while NEXAFS spectroscopy mainly describes the feature of unoccupied orbitals, which represents the electron excitation from core orbitals to virtual orbitals. Herein, we 3 present a systematic and comparative theoretical study on the carbon K -shell (1s) XPS and NEXAFS spectroscopy of the three experimentally captured isomers of C 56 and their chlorinated derivatives, namely C 2v -#913 C 56 , C s -#864 C 56 , D 2 -#916 C 56 , #913 C 56 Cl 10 , #864 C 56 Cl 12 , and #916 C 56 Cl 12 , using gradient-corrected density functional theory (DFT).…”