Lawrence Bragg explained this result by modeling the crystal as a set of discrete parallel planes separated by a constant parameter d. ![]() The derived Bragg's law is a special interpretation of Laue diffraction, where the Braggs interpreted the constructive Laue-Bragg interference in a geometric way by reflection of waves from crystal lattice planes, such that the path-difference becomes a multiple of the incident wavelength.Īccording to the 2 θ deviation, the phase shift causes constructive (left figure) or destructive (right figure) interferences. They found that these crystals, at certain specific wavelengths and incident angles, produced intense peaks of reflected radiation. History X-rays interact with the atoms in a crystal.īragg diffraction (also referred to as the Bragg formulation of X-ray diffraction) was first proposed by Lawrence Bragg and his father, William Henry Bragg, in 1913 in response to their discovery that crystalline solids produced surprising patterns of reflected X-rays (in contrast to that of, say, a liquid). ![]() However, it applies to all sorts of quantum beams, including neutron and electron waves at atomic distances if there are a large number of atoms, as well as visible light with artificial periodic microscale lattices. Such law had initially been formulated for X-rays upon crystals. It encompasses the superposition of wave fronts scattered by lattice planes, leading to a strict relation between wavelength and scattering angle, or else to the wavevector transfer with respect to the crystal lattice. In physics and chemistry, Bragg's law, Wulff–Bragg's condition or Laue–Bragg interference, a special case of Laue diffraction, gives the angles for coherent scattering of waves from a large crystal lattice. Physical law regarding scattering angles of radiation through a medium
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