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Friedel's law, named after Georges Friedel, is a property of Fourier transforms of real functions. Given a real function , its Fourier transform : has the following properties. * where is the complex conjugate of . Centrosymmetric points are called Friedel's pairs. The squared amplitude () is centrosymmetric: * The phase of is antisymmetric: * . Friedel's law is used in X-ray diffraction, crystallography and scattering from real potential within the Born approximation. Note that a (twin operation ) (aka ''Opération de maclage'') is equivalent to an inversion centre and the intensities from the individuals are equivalent under Friedel's law.〔Friedel G (1904). "Étude sur les groupements cristallins". Extract from ''Bullettin de la Société de l'Industrie Minérale'', Quatrième série, Tomes III et IV. Saint-Étienne: Societè de l'Imprimerie Thèolier J. Thomas et C.〕〔Friedel G. (1923). ''Bull. Soc. Fr. Minéral.'' 46:79-95.〕 ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Friedel's law」の詳細全文を読む スポンサード リンク
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