Effects of disorder on alkali-doped C-60 photoemission and Raman spectra

Photoemission and Raman spectroscopy performed on alkali-doped C-60 has rev ealed the origin of an additional feature often seen between the conduction bands derived from the highest occupied molecular orbital and lowest unocc upied molecular orbital. Changes in these bands due to variation of tempera ture, stoichiometry, and alkali metal are correlated with the behavior of a disorder-induced intramolecular Raman-scattering peak. Loss of interstitia l site symmetry due to thin-film disorder is suggested to be the origin of the additional electronic structure and associated Raman band. This would i mply the effects of intermolecular interactions on the electronic propertie s of alkali-doped C-60 are still not completely understood. [S0163-1829(98) 01048-0].