EXELFS对二氧化铀晶格结构的分析

本文展示了广延能量损失精细结构(EXELFS)分析用于UO_2的微区研究。首先,利用IFEFFIT软件从UO_2中氧元素的电子能量损失谱(EELS)提取EXELFS,并进行傅里叶转换得到实空间实验谱,再将实空间实验谱进行傅里叶逆变换得到倒空间实验谱。接下来,将得到的两张实验谱用IFEFFIT软件进行拟合,最终得到UO_2中氧原子周围的局域结构信息。与X射线衍射(XRD)实验数据进行比对后得知,EXELFS分析得到的UO_2晶格常数较其略小1.4%。结果表明运用EXELFS分析可以实现UO_2中晶格结构的精细分析。

EXELFS Analysis of Lattice Structure of Uranium Dioxide

The present work demonstrates that extended energy loss fine structure (EXELFS) analysis can be used to investigate the microstructure of Uranium dioxide. First, EXELFS was extracted by IFEFFIT package from oxygen-K edge in electron energy-loss spectrometry (EELS) spectrum of UO₂. Next, the EXELFS was Fourier transformed to obtain the experimental real-space spectrum, which was then back-Fourier transformed to obtain the experimental reciprocal-space spectrum. In the next step, the two experimental spectra were fitted with the IFEFFIT package to obtain information about the local structure of the oxygen atoms. Finally, the lattice constant of UO₂ determined by EXELFS analysis was found to be merely 1.4% lower than that experimentally obtained by X-ray diffraction (XRD). This result confirms that EXELFS analysis is a feasible method of investigating UO₂ microstructural information.