X-ray Absorption Spectroscopy Using X–ray Fluorescence Spectrometer

Strong characteristic Kα X-ray lines are accompanied by weak lines due to the radiative Auger effect (RAE) [1, 2]. The characteristic Kα fluorescent X-rays (K-L2,3 lines) are emitted by the 2p→1s electric dipole transition after one of the 1s electron photoionization, Though the probability is less than 0.01, one of the 2p electrons is excited into an unoccupied discrete or continuum level simultaneously with the Kα X-ray fluorescence, because of the perturbation of the sudden change of the atomic potential before and after the 2p→1s electric dipole transition. This many body effect is called the radiative Auger effect. Kawai et al. [3] pointed out that the profiles of the RAE X-ray fluorescence (XRF) spectra resembled to that of the X-ray absorption edge, and Hayashi et al. [4] demonstrated that we could perform the extended X-ray absorption fine structure (EXAFS) spectroscopy of aluminum metal by the Fourier transform of the line shape of RAE in XRF spectra. Kawai et al. [5] reported that the radial distribution functions around the X-ray emitting atom in aluminum oxides were obtainable with the accuracy of 0.03C by the Fourier transform of the RAE in the XRF spectra. Tanuma et al. [6] demonstrated that the EXAFS-like oscillation was observable in the electron probe X-ray microanalyzer (EPMA) spectra of 1 μm diameter area. Kawai et al. [7, 8] proposed to call this EXEFS (abbreviation of extended X-ray emission fine structure). The present authors reported Si K-edge XANES (X-ray absorption near edge structure) of Si and SiO2 measured by the present method [9, 10]. Kawai et al. [11, 12] reported micro-XANES of various Si compounds by the use of EPMA.