Ultraviolet photoelectron spectra of Lu atoms encapsulated C2v–C82 fullerenes

Ultraviolet photoelectron spectra of Lu@C82(I), Lu2@C82(II) and Lu2C2@C82(II) were measured. The spectral onsets (Eonset) of these fullerenes indicate their semi-conductive nature. While their deeper valence band UPS derived from the σ-electrons of C82 cage are almost identical, the upper valence band UPS of Lu@C82(I) is significantly different from those of Lu2@C82(II) and Lu2C2@C82(II). Lu4f7/2 and Lu4f5/2 levels are observed in the UPS, which could be the first finding of the inner levels derived from the encapsulated species. These levels deviate slightly when encapsulated species change, which could be due to the difference in the amounts of electrons on Lu atom(s).