X-ray absorption spectroscopy (XAS) of size-selected free cerium-oxide cluster ions has been carried out by employing an ion trap. X-ray absorption spectra of Ce2O3+ and Ce2O5+ were obtained in the energy range of the Ce M-edge. The spectra consisted of two prominent peaks corresponding to Ce M5- and M4- white line peaks. The photon energies of the peaks showed that the charge state of Ce in Ce2O3+ was comparable with a formal valence number. On the other hand, the estimated charge state of Ce in Ce2O5+ was much smaller than a formal valence number, which was consistently understood by assuming that Ce2O5+ has a Ce2O3-O2 configuration with a molecular O2 adsorbed. It was thus demonstrated that an ion trap facilitates XAS measurement for determining charge states of atoms in a free cluster.
|ジャーナル||Journal of Physics B: Atomic, Molecular and Optical Physics|
|出版ステータス||出版済み - 3 16 2016|
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