X-ray Multiple-wave Diffraction Anomalous Fine Structure

Multiple-wave Diffraction Anomalous Fine Structure (MDAFS), a new method combining the X-ray multiple-wave diffraction with diffraction anomalous fine structure (DAFS) technique, provides the long-range order structure information by measuring the multiple-wave diffraction profiles in the vicinity of an absorption edge. The real part of dispersion correction and fine structure function can be obtained directly by multiple diffraction analysis without using Kramers-Krong relations (KKR) and kinematical fitting of diffracted intensity. The useful X-ray phase information of the structure-factor multiplets, linking the image part with the real part of the structure factor, can easily substitute the Kramers-Kronig relations. Moreover, the constraint imposed by the additional reflection on the diffraction geometry makes the MDAFS a much more wavevector and site-sensitive technique than the two-ware DAFS for the measurements. Here we report a three-wave diffraction measurement of GaAs single crystal near the Ga K-edge and show how MDAFS analysis works.