EXELFS Analysis of Lattice Structure of Uranium Dioxide

Abstract

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.