ISSN:
1600-5724
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
The intensities of Bragg reflexions generally show a large change in the energy region near an absorption edge of the constituent atoms. The integrated reflecting powers, Rh(ω) and R-h(ω), measured in the energy-dispersive mode, have been calculated for a Friedel pair of reflexions from a noncentrosymmetric crystal. In order to investigate the effect of thermal vibrations, both perfect and mosaic cases are considered. It has been found that the values of the isotropic temperature factors strongly affect the shapes of the curves for Rh(ω) and R-h(ω). It is shown, for CuI, that the intensity ratio Rh(ω) between the Friedel pair tends to the limit value, unity, when the relevant Bj factors become large: i.e. large thermal vibrations screen the effects due to the polarity.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0567739479001698
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