Identification of Four C 40 Isomers by Means of a Theoretical XPS/NEXAFS Spectra Study

XPS and NEXAFS spectra of four stable C$_{40}$ isomers[29(C$_{2}$), 31(C$_{s}$), 38(D$_{2}$) and 39(D$_{5d}$)] have been investigated theoretically. We combined the density functional theory and full core hole potential method to simulate C 1s XPS and NEXAFS spectra for nonequivalent carbon atoms of four stable C$_{40}$ fullerene isomers. The NEXAFS showed obvious dependence on the four C$_{40}$ isomers and XPS spectra are distinct for all four isomers, which can be employed to identify the four stable structures of C$_{40}$. Furthermore, the individual component of spectra according to different categories have been investigated and the relationship between the spectra and the local structures of C atoms was also explored.Furthermore, the individual component of spectra according to different sorts have been investigated and the relationship between the spectra and the local structures of C atoms was also explored.