Open AccessSynchrotron radiation photoemission study of Yb2.75C60
Author(s) -
He Shaolong,
Hong-Nian Li,
Xiaoxiong Wang,
Haiyang Li,
Kurash Ibrahim,
Qian Huang,
Run Su,
Mamatimin Abbas,
Jun Zhong,
Hong Chang
Publication year - 2005
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.54.1400
Subject(s) - photoionization , synchrotron radiation , atomic physics , photon energy , spectral line , inverse photoemission spectroscopy , angle resolved photoemission spectroscopy , photoemission spectroscopy , electron , binding energy , valence (chemistry) , fermi level , photon , homo/lumo , valence electron , physics , ionization , ion , optics , molecule , quantum mechanics , astronomy
The Yb275C60 thin film was prepared and studied by using the synchrotron radiation ultraviolet photoemission spectroscopy(PES) in an ultrahighvacuum system. The spectral line obtained in the range between the Fermi level and 5 eV binding energy consists of those lines from the valence band (the molecular orbital LUMO, HOMO and HOMO1 derived energy bands of C60) and core levels(Yb 4f7/2 and 4f5/2). Taking into account the variations of the photoinization cross sections of C 2p and Yb 4f with different photon energies, we have measured the photoemission spectra under the condition of varying photon energies, and carried out simulations to deduce the component contributions. The peak positions, widths and intensities for the components are obtained quantitatively. The results reveals that the photoemission of 4f electrons has a significant intensity with the photon energies larger than 300 eV, and that the measured spectra depart drastically from the density of states of the valence band. To observe the valence band structure, one should carry out the PES measurements by using photons with energies less than 300 eV. The photoionization crosssection oscillation is also observed in Yb275C60 with almost the same oscillation period as that for pure C60 However, the oscillation amplitude is obviously smaller than that for pure C60, which reveals that the chemical environment of C60 in compounds has nonnegligible effects on the photoionization crosssection oscillation phenomenon.