Temperature dependence of the electronic and vibrational excitations of C-60 adsorbed on Si(100)-2x1

Electron spectroscopic studies of C-60 monolayers adsorbed on a Si(100)-2 x 1 surface as a function of annealing temperature indicate three adsorption states. At room temperature C-60 interacts weakly with the surface and in consequence the electronic and vibrational excitations of the molecule are only slightly perturbed. Above 873 +/- 10 K changes in electronic and vibrational excitations indicate that, although the molecule remains intact, the nature of the surface-molecule bond changes, leading to what may be regarded as a strongly chemisorbed 'precursor' state to cage opening and destruction. Beyond 1048+/-10 K the fullerene molecules begin to break up, with some carbon atoms remaining on the substrate surface in the form of a carbide.