Localization of substrate-induced modification in the electronic structureof ${\mathrm{C}}_{60}$sat fullerene-metal interfaces

Photoemission and electron-energy-loss-spectroscopy studies of ${\mathrm{C}}_{60}$ films deposited on Au(110) demonstrate that only the first layer of molecules, directly in contact with the metal substrate, display significant changes in electronic structure. If the Au(110) surface is precovered with Cs it is found that, at 298 K, the Cs can diffuse readily into a ${\mathrm{C}}_{60}$ thin film, preventing the formation of a localized interface. However, if a Cs precovered Au(110) sample is held at 98 K, subsequent deposition of ${\mathrm{C}}_{60}$ results in the formation of a spatially localized interface with only the closest two fullerene layers to the original metal surface modified by charge transfer.