X-ray absorption fine structure, as an advanced characterization technique for the local structure analysis of materials, can provide more accurate atomic structure coordination information in the short-range structure range than X-ray crystal diffraction.

For the X-ray absorption curve of non-isolated atoms, due to the coherent superposition of the photoelectron outgoing wave of the central atom and the elastic backscattering wave generated by the neighboring atom, the linear absorption coefficient on the high-energy side of the absorption edge deviates from the monotone change, forming a fluctuating oscillation structure related to the wavelength of the photoelectron, the type and structure of the coordination atom.

X-ray absorption fine structure composition:

XANES: Absorption atomic electronic structure

EXAFS: The structure information of adjacent coordination atoms of absorbed atoms