Photoelectron spectra of a higher fullerene compound C₈₂ and its potassium complex

Photoelectron spectra of C₈₂, which has been reported to contain metal atoms inside, are measured with a synchroton radiation light source. The spectra resemble those of C₈₄. The spectra begin at 1.1₅ eV below the Fermi level (E_f). The first band consists of two peaks located at 2.2 eV and 3.3 eV accompanied by a slight shoulder structure at the lower binding energy side. This shoulder is not observed in C₈₄. The intensity of the two peaks of the first band oscillates with the incident photon energy change, as are observed in C₆₀, C₇₀ and C₈₄. The second band locates between 4 and 6.2 eV with a peak at 5.3 eV and a shoulder at the lower binding energy side. The third band locates between 6.2 and 9 eV and consists of a peak at 7.8 eV and a distinct shoulder at 6.5 eV. Potassium dosing brings a new band between the E_f and the first band and its intensity grows as the potassium dosage increases. The spectral onset approaches toward the E_f in accordance with increase of potassium dosage but it does not cross the E_f, which indicates a semiconductive nature of K_xC₈₂.