ISSN:
1600-5724
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
Advantages of high-angle double-crystal X-ray diffractometry (HADOX) have been re-examined. It is found that, by extending the Bragg angle \theta up to 89.99^{\circ}, the accuracy of a change in the lattice spacing to one part in 10^{9}–10^{10} can be attained in proportion to \tan\theta. In such a case, the dispersion-free condition is so serious that the spacing of the two crystals should be equal within one part in 10^{6}. Therefore, this method is appropriate for determining the thermal expansion coefficient in a limited temperature range. To cover a wide temperature range, the temperature of the reference crystal must be adjusted according to the temperature of the specimen crystal; the lattice spacing as a function of temperature can be determined by integrating the temperature derivative of the spacing.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0108767301014064
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