Valence-selective XAFS spectroscopy of lanthanides using "the forgotten emission line", L_<γ4>

我们开发了一种新的分析方法，利用高分辨率的L_<γ - 4>发射来表征Eu和Ce材料的化学状态。鉴于L_<γ4>的发射非常微弱，迄今为止一直被忽视，我们使用多晶多探测器光谱仪准确地获得了高分辨率（<1eV）的Eu/Ce L_<γ4>发射光谱。Eu/Ce光谱的差异取决于Eu离子的价态和Ce离子的化学环境。通过部分荧光产额（PFY）测量，证明了EuL_<γ - 4>在价选择性XAFS光谱中的适用性。提出了CeL_<γ - 4>在Ce材料中电荷转移研究中的可能应用。

We have developed novel analytical methods for the characterization of chemical states of Eu and Ce materials using highly resolved L_<γ4> emissions. Whereas the L_<γ4> emissions are very weak and hitherto neglected, we accurately obtained high-resolution (<1eV) Eu/Ce L_<γ4> emission spectra by the use of a multicrystal, multidetector spectrometer. The Eu/Ce spectra exhibited substantial differences depending on the valence state of Eu ions/on the chemical environments of the Ce ions. The applicability of the EuL_<γ4> to valence-selective XAFS spectroscopy was demonstrated through partial fluorescence yield (PFY) measurements. Possible applications of the CeL_<γ4> to the studies of charge transfers in Ce materials were suggested.