Temperature-dependent chemisorption of C60 on Mo(110): precursors to cage destruction

The catalytically promoted decomposition of C60 has recently been observed on a variety of surfaces upon which the molecule can chemisorb strongly. It is now becoming clear that destruction occurs via conversion of a relatively weakly bound state arising from room-temperature adsorption into a strongly bound state in competition with molecular desorption. On Mo(110) a progression through four distinct chemisorbed states is observed, from weakly bound through the immediate precursor to fragmentation, with increasing hybridisation between molecule and substrate. This change in adsorption state is reflected in both the C 1s core-level position and the width and position of the valence states of the molecule. We present X-ray photoelectron spectroscopy and ultraviolet photoemission spectroscopy results on this system, and an interpretation of the evolution of spectral features as a function of adsorption state.