Observational studies of imperfect carbon cage structures of C 60 by high-resolution scanning tunnelling microscopy

Anomalies in the morphology of the carbon cage of C 60 clusters have been investigated with atomic level resolution using high-resolution scanning tunnelling microscopy. The imperfect carbon cages have been resolved in the finest detail, which, for the first time, provide a remarkable confirmation of a variety of theoretical defect structures recently predicted by molecular dynamics simulations. The observed tunnelling spectra are consistent with the theoretical contention that the gap between the highest occupied molecular orbitals (HOMO) and the lowest unoccupied molecular orbitals (LUMO) for the clusters is decreased with the presence of defects.