S.J. Chase

Photoemission Spectra of C60 Clusters in Metal and Nonmetal Systems

Changes in the weighted electronic density of states of C60 molecules deposited on a variety of substrates have been studied by HeI ultraviolet photoemission (UPS). Spectra of C60 deposited on polycrystalline Ag exhibit a C60, LUMO-derived band which appears to originate in interactions at the interface. C60 was also exposed to Rb, developing a LUMO-derived band and similar phase characteristics to those observed in KxC60 compounds. The effect of atomic H as an adsorbate was also investigated. While adsorbates generally show increased broadening of the πp and σp occupied states of C60 with increasing coverage, exposure to atomic H resulted in spectra where the distinct molecular features were completely lost, bearing a distinct resemblence to graphite. However, Raman spectroscopy indicates the essential C60 structure has not been changed.