Debye-Waller Factors In Diffraction Anomalous Fine-Structure. J.O. Cross, L.B. Sorensen and J.J. Rehr

Expressions for the Debye-Waller factors in diffraction anomalous fine-structure have been obtained using the scattering path formalism from x-ray absorption fine-structure (XAFS) theory. The diffraction fine-structure is found to introduce disorder terms into the atomic scattering factors f=f₀+f'+if'' through near-neighbor coordinate dependence in the anomalous scattering. This gives XAFS-like Debye-Waller factors in the diffraction fine-structure in addition to the usual diffraction Debye-Waller factors due to disorder terms in the phases Q.R. Differences in the polarization dependencies of Thomson scattering and photoelectron emission lead to orthogonal sensitivities to disorder between the XAFS-like Debye-Waller factors, which cause the fine-structure to decay exponentially with energy, and the diffraction Debye-Waller factors, which cause the peak intensities to decay exponentially with Q².