Self-defined transition states in hybrid C70-Au clusters by the scanning tunnelling microscope tip

Manipulation of C70-Au hybrid nanoclusters was investigated using a scanning tunneling microscope (STM) tip. We demonstrate that removing a selected C70 molecule from the cluster by STM-tip resulted in an intermediate transition state without thermal decomposition. The molecule rotates and diffuses around the cluster and leaves the cluster without taking an additional molecule and Au atoms due to the rather weak interaction between molecules and the surface atoms. After removing C70 molecule, the van der Waals interaction among C70 molecules squeeze the cluster components and move out the Au atoms in the island. This self-transition-state is due to a week charge transfer between the molecules and the surface. The extraction of the molecules in a ring cluster resulted in polygonal Au island formation in a major surface direction of Au(111). This preferential state for Au atoms after manipulation is staying on the surface because of a strong charge transfer with the surface atoms and thermal energy of the surface rather than C70 molecules.