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Kinematic Diffraction
Kinematic diffraction is an approximation for diffraction of waves. It assumes that the waves are only scattered once, neglecting multiple scattering. For linear wave equations, it involves summing the contribution of the partial waves emanating from different scatterers, where only the incident field drives the scattering. As a consequence, the Fraunhofer diffraction, far-field amplitude essentially corresponds to the Fourier transform of the scattering length density, which would be the charge density for x-rays and the electrostatic potential for electrons. It is typically understood as the Born approximation applied to a number of scatterers, and as such is often used for X-ray crystallography. The corresponding full theory is called the dynamical theory of diffraction. For x-rays and in electron diffraction different approaches are used to calculating the dynamical diffraction for transmission with high-energy electrons as well as for low energy electron diffraction or reflectio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Diffraction
Diffraction is the deviation of waves from straight-line propagation without any change in their energy due to an obstacle or through an aperture. The diffracting object or aperture effectively becomes a secondary source of the Wave propagation, propagating wave. Diffraction is the same physical effect as Wave interference, interference, but interference is typically applied to superposition of a few waves and the term diffraction is used when many waves are superposed. Italian scientist Francesco Maria Grimaldi coined the word ''diffraction'' and was the first to record accurate observations of the phenomenon in 1660 in science, 1660. In classical physics, the diffraction phenomenon is described by the Huygens–Fresnel principle that treats each point in a propagating wavefront as a collection of individual spherical wavelets. The characteristic pattern is most pronounced when a wave from a Coherence (physics), coherent source (such as a laser) encounters a slit/aperture tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
