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Three-beam resonant X-ray diffraction in germanium - Laue transmission cases
Gunnar Thorkildsen1, Helge B Larsen, Edgar Weckert
1Department of Mathematics and Natural Science, University of Stavanger, N-4036 Stavanger, Norway. gunnar.thorkildsen@uis.no
Summary
Investigating X-ray diffraction in germanium crystals near the K-absorption edge reveals that crystal size, not resonance effects, primarily influences three-beam diffraction asymmetry. Tabulated scattering factors may require adjustment near absorption edges.
Area of Science:
- Solid-state physics
- Materials science
- Crystallography
Background:
- X-ray diffraction is crucial for analyzing crystal structures.
- Understanding multi-beam interactions is essential for advanced diffraction techniques.
- Resonant scattering effects can influence diffraction patterns near absorption edges.
Purpose of the Study:
- To examine the perturbation of two-beam diffracted power by a third lattice node in germanium crystals.
- To investigate the influence of crystal size and resonant scattering on three-beam X-ray diffraction profiles.
- To analyze diffraction phenomena near the K-absorption edge.
Main Methods:
- Experimental examination of three-beam X-ray diffraction in a small, finite germanium crystal.
- Application of fundamental X-ray diffraction theory.
- Inclusion of Cromer-Liberman calculations for resonant scattering terms.
- Analysis incorporating beam divergence and dynamical block size as adjustable parameters.
Main Results:
- Experimental results are well-described by established diffraction theory and scattering calculations.
- Observed asymmetry in three-beam profiles is primarily attributed to crystal size effects.
- Resonance effects related to the triplet phase sum showed minimal impact on profile asymmetry.
- Evidence suggests a reduction in f' values compared to tabulated data near the absorption edge.
Conclusions:
- Crystal size is the dominant factor in three-beam diffraction asymmetry in germanium near the K-absorption edge.
- Standard diffraction theory adequately describes the observed phenomena.
- Further refinement of scattering factor values may be necessary for precise analysis near absorption edges.
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