ISSN:
1600-5724
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
The basic assumptions and limits of the BJR dynamical theory of electron diffraction are discussed. In the two-beam approximation the absorption coefficient derived in the BJR theory takes account of the thermal diffuse scattering and of the weakly excited beams, but neglects their dynamical interaction with the two strong beams. This seems to be a suitable approximation for real crystals with defects and grain boundaries as in polycrystalline foils. For thick perfect single crystals a better approximation may be obtained by removing the weak beam term from the absorption coefficient, leading to the results of Hall & Hirsch. In both cases the same simple expression for the temperature dependence of the two strong beams is obtained for anomalous transmission, being in good agreement with experiment.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0567739470000153
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