Photoelectron spectra of thulium atoms encapsulated C_(82) fullerene, Tm_2@C_(82) (III) and Tm_2C_2@C_(82) (III)

摘要

Ultraviolet photoelectron spectra (UPS) and X-ray photoelectron spectra (XPS) of two thulium atoms and thulium-carbide cluster entrapped fullerenes, Tm_2@C_(82) (III) and Tm_2C_2@C_(82) (III), were measured using synchrotron radiation and MgKα X-ray light sources. The UPS spectral onset energy of these endohedral fullerenes is around 0.9 eV, which is smaller than that of 1.2 eV of empty C_(82). The UPS of Tm_2@C_(82) (III) and Tm_2C_2@C_(82) (III) resemble each other. Further, the UPS of Tm_2@C_(82) (III), Y_2@C_(82)-C_(3v) and Er_2@C_(82)-C_(3v) are almost identical and as well as are Tm_2C_2@C_(82) (III), Y_2C2@C_(82)-C_(3v) and Er_2C_2@C_(82)-C_(3v). The XPS Tm4d_(5/2) peaks of Tm_2@C_(82) and Tm_2C_2@C_(82) appear at higher binding energy region than that of Tm@C_(82), which suggests the oxidation states of Tm atoms in Tm_2@C_(82) (III) and Tm_2C_2@C_(82) are higher than that in Tm@C_(82).