| This paper discusses the investigation and manipulation by scanning tunneling microscopy of new fullerene derivative molecules synthesized specifically to achieve nanoscale motion. Two, three, and four-fullerene molecules with connecting oligo (phenylene-ethynylene) structures have been studied statically, and manipulated dynamically to ascertain the type of motion they undergo under direct tip-manipulation and thermal excitation. The dimer molecules were found to have a low surface-diffusion barrier on a Au(111) surface, and were seen to pivot around a single fullerene between scans. Trimer molecules were heated to temperatures where pivoting motion was observed over time spans of minutes, but did not illustrate significant translational motion. Quadrimers, or nanocars, were both directly tip-manipulated and thermally annealed to examine their surface-mechanics, and were found to prefer motion along an axis perpendicular to the oligo (phenylene ethynylene) axle structure, suggesting a coordinated rolling of the fullerenes. |
