ISSN:
1600-5767
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Geosciences
,
Physics
Notes:
The assumptions in the Borie & Sparks [Acta Cryst. (1971). A27, 198–201] procedure for the separation of order- and displacement-dependent components of diffuse X-ray scattering from a binary system AB are examined with the use of the concentration deviation (spin-like) notation. The more limiting assumption, that the structure-factor ratio η = (mAfA + mBfB)/(fA−fB) is constant in reciprocal space, is shown to produce an incomplete separation for normal variations in η. A matrix-inversion method for completing the separation is suggested for those cases in which the approximate equality of the Debye–Waller factors (DWF) of the individual atomic species indicates that some terms of the scattering equation may be neglected. The extension suggested by Ramesh & Ramaseshan [Acta Cryst. (1971). A27, 569–572] that anomalous dispersion induced changes in η could be used to separate the atomic static displacement properties of the various atomic pairs is shown to require a change in η greater than the variation of η across the reciprocal-space volume. Some difficulties of obtaining such a change are pointed out.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0021889875009740
