Adsorptidn of Sm on C₆₀ Film

Using photoemission spectroscopy, we have studied the adsorption of Sm on C₆₀ film. At the first stage of Sm adsorption, the C₆₀ valence band shifts to the high binding energy side. The maximum shift is about 0.4eV. In the meantime, there appears a new structure at the upper side of the highest occupied molecule orbit (HOMO) band, which comes from the hybrid of the Sm 4f ⁵ state and C₆₀ HOMO band. As Sm coverage increases the Sm electron is in a kind of Sm²⁺ state due to the forming of Sm cluster on the surface.