Electronic structure and growth mode of the early stages of C60 adsorption at the Ag(001) surface

The electronic structure and growth mode of C 60 molecules deposited on Ag(001) have been studied as a function of deposition parameters and annealing temperature. The measurements show that C 60 molecules are chemically bound to the Ag(001) surface even when deposited at 150 K, and the bond properties do not change significantly after annealing up to 670 K. In the resulting ordered C 60 overlayer, a mixed contrast of the buckyballs, as seen by scanning tunneling microscopy, is discussed in terms of non-equivalent orientations of the adsorbed molecules.