At what energy range does EXAFS operate?

Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy primarily operates at energy ranges above the edge of the absorption spectrum where the X-ray absorption transitions occur. EXAFS begins at energies just above the absorption edge of a specific element, which typically involves photons with energies greater than the binding energy of core electrons of the element being studied. This allows for the measurement of oscillations in absorption that arise from the interference effects of photoelectrons scattered by neighboring atoms.

The energy range for EXAFS starts shortly after the edge where the initial X-ray absorption occurs and can extend significantly higher, often up to several hundred eV above the edge energy, well into the range that is above typical NEXAFS (Near Edge X-ray Absorption Fine Structure) energies, which are located closer to the absorption edge itself.

Understanding these operational ranges is essential for using EXAFS effectively in structural analysis and can distinguish it from other related techniques. This is why the selected answer indicating EXAFS operates greater than the NEXAFS region is accurate, as EXAFS represents a different interaction of X-rays with matter than what is typically observed in NEXAFS spectroscopy.