Instability of C60+ on Ni(100) in surface collisions

Collisions of C 60 + -ions with a nickel (100) surface in ultra high vacuum have been studied. Fullerene ions emerging from the surface after impact were not observed. Auger spectroscopy reveals an increasing carbon coverage of the surface as the exposure dose of C 60 + increased until saturation is reached. Low energy electron diffraction shows formation of ac(2×2) carbon superstructure ofp4g-symmetry. There is strong evidence, that the observed instability of C60 is induced by a chemical reaction at the surface and that the Ni−C bonds formed lead to the superstructure.