ULTRAVIOLET PHOTOELECTRON-SPECTRA OF C-76 AND KXC76

Ultraviolet photoelectron spectra of C76, one of the fullerene family of compounds, have been measured with a synchroton radiation light source. The photoemission spectral onset is 1.3 eV below the Fermi level, which is equal to that of C84 but is about 0.5 eV smaller than that of C60 or C70. The relative intensity of the photoemission spectral features is independent of the incident photon energy change. Photoemission spectral changes for C76 during potassium dosing are also measured. A new band becomes distinct between the Fermi level and the HOMO band, when the potassium content (x in KxC76) is equal to or greater than 1.1. The spectral onset moves toward the Fermi level with increasing potassium dosage, approaching it but never crossing it. This indicates that potassium-dosed C76 could be a narrow gap semiconductor.