Unusual molecular orientation and frozen librational motion of C-60 on Cu(110)

Full-hemispherical angle-scanned x-ray photoelectron diffraction has been u sed to investigate the molecular orientation and librational motion of C-60 molecules adsorbed on the Cu(110) surface. The molecules are found to face the substrate surface in an unusual bonding configuration, rotating their symmetry axes by a few degrees away from the high-symmetry directions of th e Cu(110) substrate. Despite the asymmetric molecular orientation, the C-60 molecules are immobile, i.e., they show no librational motion, up to tempe ratures well above the C-60 sublimation temperature. [S0163-1829(99)01428-9 ].