Dynamical theory of diffraction: Difference between revisions

Revision as of 22:55, 5 October 2008

Revision as of 22:56, 5 October 2008

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The '''dynamical theory of diffraction''' describes the interaction of [[wave]]s with a regular lattice. The wave fields traditionally described are [[X-rays]], [[neutron radiation|neutron]]s or [[electrons]] and the regular lattice atomic crystal structures or nanometer scaled multi-layers or self arranged systems. In a wider sense, similar treatment is related to the interaction of light with optical band-gap materials or related wave problems in acoustics.

[[Image:LaueBraggGeometry.png|thumb|right|250px|Laue and Bragg geometries, top and bottom, as distinguished by the [[Dynamical theory of diffraction]] with the Bragg diffracted beam leaving the back or front surface of the crystal, respectively. ([http://www.kdliss.de/KDL/DissLiss/index.html Ref.])]]

[[Image:RLaueBragg.png|thumb|right|250px|Reflectivities for Laue and Bragg geometries, top and bottom, respectively, as evaluated by the [[Dynamicaldynamical theory of diffraction]] for the absorption-less case. The flat top of the peak in Bragg geometry is the so-called [[Darwin Plateau]]. ([http://www.kdliss.de/KDL/DissLiss/index.html Ref.])]]

==Principle of theory==

The '''dynamical theory of diffraction''' considers the wave field in the periodic potential of the crystal and takes into account all multiple scattering effects. Unlike the [[Diffraction formalism|kinematic theory of diffraction]] which describes the approximate position of [[Bragg diffraction|Bragg]] or [[X-ray crystallography|Laue diffraction]] peaks in [[reciprocal space]], '''dynamical theory''' corrects for refraction, shape and width of the peaks, extinction and interference effects. Graphical representations are described in [[dispersion surfaces]] around reciprocal lattice points which fulfill the boundary conditions at the crystal interface.

==Outcomes==