Surface extended x-ray-absorption fine-structure spectroscopy measurement using the evanescent-wave effect of fluorescent x rays

The surface extended x-ray-absorption fine structure (EXAFS) can be measured by detection of fluorescent x rays at a small glancing angle (in the vicinity of the critical angle for total reflection). This is based on the emission of fluorescent x rays from the surface region due to internal excitation of the fluorescent x-ray evanescent waves. EXAFS spectra of constant sampling depth from the interface can be obtained independent of incident x-ray wavelength.