![]() ![]() X-rays can also be generated by decelerating electrons in a target or a synchrotron ring. Two common targets are Mo and Cu, which have strong K(alpha) X-ray emission at 0.71073 and 1.5418 Å respectively. X-ray tubes generate X-rays by bombarding a metal target with high-energy (10 - 100 keV) electrons that knock out core electrons.Īn electron in an outer shell fills the hole in the inner shell and emits an X-ray photon. X-ray diffractometers consist of an X-ray generator, a goniometer and sample holder, and an X-ray detector such as photographic film or a movable proportional counter. Since hydrogen atoms have very little electron density, determining their positions requires extensive refinement of the diffraction pattern.Įlectron diffraction and neutron diffraction are sensitive to nuclei and are often used to accurately determine hydrogen positions. A high-energy stream of electromagnetic radiation having a wavelength shorter than that of ultraviolet light but longer than that of a gamma ray. X-rays are predominantly diffracted by electron density and analysis of the diffraction angles produces an electron density map of the crystal. Lawrence Bragg devised the concept of XRD Among other methods, femtosecond X-ray diffraction stands out as a direct probe of both atomic motions and changes of the electronic charge distribution induced. ![]()
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