C. Cepekl(1), M. Sancrotti(1), Th. Greber(2), R. Fase(3), and J. Osterwalder(2)(1)Laboratorio Nazionale TASC-INFM, Padriciano 99, 134012 Trieste, Italy (2)Institut für Phyzik, Zürich Universitä, Irchel, Zurich, CH (3)EMPA, CH-8600 Duebendorf, Switzeland

Recent work [1] on the chemisorption of C60 molecules on single crystals has shown that the rotational modes are frozen thus making it possible to get photoelectron diffraction patterns from the C-atoms of the C60 balls. We explored by photoelectron diffraction two different systems: C60/Ag(001) and C60/Cu(221) interfaces. The importance of these systems relies upon: i) the observation via STM of two distinct chemisorption sites for the buckyballs in the former case; ii) the existence of (111) terraces along the [-110] direction with a lateral size comparable with the buckyball size in the latter case. The role played by steps in tne chemisorption of C60 is thus addressed and this might be important as to the possiblility of faabricating electronic devices where chains of fullerenes are artificially produced [2[.

[1]R. Fasel et. Al., Phys. Rev. Lett. 76 (1996) 4733

[2] M. T. Cuberes, R. R. Schittler, and K. Cimzewski, Appl. Phys. Lett. 69 (1996) 3016