OBSERVATIONAL STUDIES OF IMPERFECT CARBON CAGE STRUCTURES OF C-60 BY HIGH-RESOLUTION SCANNING-TUNNELING-MICROSCOPY

Anomalies in the morphology of the carbon cage of C-60 clusters have b een investigated with atomic level resolution using high-resolution sc anning: tunnelling microscopy. The imperfect carbon cages have been re solved in the finest detail, which, for the first time, provide a rema rkable confirmation of a variety of theoretical defect structures rece ntly predicted by molecular dynamics simulations. The observed tunnell ing spectra are consistent with the theoretical contention that the ga p between the highest occupied molecular orbitals (HOMO) and the lowes t unoccupied molecular orbitals (LUMO) for the clusters is decreased w ith the presence of defects.