The structure of submonolayer C_60 film sdeposited on Ag(001) is studied as a function of the substrate temperature in the range 100-700 K. Morphological aspects such as island shape and perferential nucleation sites are in agreement with the theory of submonolayer deposition. A peculiar irreversible transition which leads to the onset of brightness differences between molcules of the same film is observed at around 300 K. This effet is ascribed to electronic differences due to non-equivalent orientation of the C_60 molecules on the surface rather than to morphological differences induced by a surface reconstruction.
展开▼
