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X-ray diffraction

X-ray diffraction

X-ray diffraction is a technique based on the interaction between X-rays and matter. William Lawrence Bragg and his father William Henri Bragg were awarded the Nobel prize in 1915 because of their development.

Diffraction results from the interference between X-rays that illuminate a material whose atoms are periodically disposed. X-rays are reflected on the different crystallographic planes of the material. There is a difference in the path of X-rays reflected in the different crystallographic planes of the material. The path difference is at the origin of interference phenomena between the different reflected beams, giving rise to maxima and minima of intensity. The angle where the maxima appear as well as their intensity contain structural information on the material. The analysis of these quantities allows to obtain a valuable information : the atomic positions.

X-ray diffraction principle. X-ray interacting with a periodic system give rise to an intensity redistribution after interaction. The analysis of this intensity as well as its angular distribution allows to determine the atomic structure of the material.

Film on crystallography and reciprocal space. Courtoisy of Julien Bobroff.