A method for correcting self-absorption shown in fluorescence XAFS spectra

Abstract

X-ray-absorption fine-structure (XAFS) measurement by the fluorescence-yield (FY) method can be applied to samples of various shapes and concentrations. However, it is known that XAFS spectra obtained by the FY method do not precisely reflect the original X-ray absorption of the sample due to the self-absorption effect. We therefore propose a method for correcting the self-absorption by using FY XAFS spectra of original and diluted samples. The proposed self-absorption correction method can be applied to samples with unknown compositions. The effectiveness of the correction method was evaluated by applying it to the FY XAFS spectra of several iron oxides and their mixtures. As a result, the corrected FY XAFS of Fe K-edge spectra were almost identical to the XAFS spectra obtained by the transmission method. The suppressed EXAFS oscillations of the FY XAFS spectra were also recovered. These results validate the effectiveness of the proposed correction method. They also demonstrate that the corrected XANES spectra can be applicable to linear combination fitting analysis.