Anomalous X-Ray Scattering

The availability of tunable synchrotron radiation has made it possible to perform systematic X-ray diffraction studies in regions of anomalous scattering near absorption edges, e.g., in order to derive phase information for crystal structure determination. We give an overview of recent experimental and theoretical work and discuss the properties of the anomalous atomic scattering factor, with emphasis on threshold resonances and damping effects. The results are applied to a discussion of the very strong anomalous dispersion recently observed near the L3 edge in a cesium complex [11]. We also discuss briefly other systems where similar behaviour can be expected. Finally, we discuss the influence of solid state and chemical effects on the absorption edge structure.

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