Photoelectron spectra of metallofullerenes, GdC82 and La2C80: Electron transfer from the metal to the cage

Ultraviolet photoelectron spectra of metallofullerenes, GdC82 and La2C80 were measured with synchrotron orbital radiation. The specimens were dried-up films prepared from their solution instead of the sublimed films commonly adopted for the measurement. GdC82 gave structure rich spectra reflecting its electronic structure. The band intensity of the GdC82 spectra depends on the incident photon energy, as observed in other fullerenes. The similarity of the GdC82 spectra to those of LaC82 indicates that their electronic structures are analogous. The spectrum of La2C80 does not show any characteristic structures that have been observed in those of other fullerenes, and it resembles that of amorphous carbon. The C ls core photoelectron spectra of these metallofullerenes obtained with the Mg Kα radiation are also presented.