Intramolecular structures ofC60molecules adsorbed on the Cu(111)-(1×1) surface

The structure of ${\mathrm{C}}_{60}$ molecules adsorbed on the Cu(111)-(1×1) surface has been investigated by scanning tunneling microscopy (STM). Bias voltage dependent STM images of individual ${\mathrm{C}}_{60}$ molecules in the monolayer film showed unique intramolecular structures with a threefold symmetry. The observed images agree well with those calculated using the local density approximation. With charge transfer from the Cu(111) substrate to the monolayer film, the ${\mathrm{C}}_{60}$ molecule ratchets to threefold hollow sites.