Change in Chemical Bonding States in Electron-Irradiated Graphite

The damage process in electron-irradiated graphite was investigated by electron energy-loss spectroscopy (EELS). An analysis of the extended energy-loss fine structure (EXELFS) revealed that new components with slightly different interatomic distances grew with irradiation time in the first-nearest neighbor coordination shell. In addition, the energy-loss near edge structure (ELNES) exhibited features characteristic of higher fullerenes. The consistency of these results can be explained by the formation of non-sixfold atomic rings by electron irradiation, similar to fullerenes.