Publication Date:
1996-01-01
Description:
Partially or fully ordered distributions of two elements on two crystallographically different positions play an increasingly important role in material and earth sciences. As a consequence of the simple principle ‘what can be studied in reciprocal space (or appropriately selected parts of it), does not deserve Fourier mapping in direct space’, we discuss:1. For determining distributions of elements with similar atomic numbers, a single-wavelength measurement suffices and gives better results than the combination of data measured at two wavelengths providing different anomalous scattering.2. The least-squares technique or other procedures employing carefully selected reflections are superior to electron counting from Fourier maps. In particular, a two-The conclusions are valid under the assumption that the crystal structure is sufficiently well known, except an ‘order parameter’ describing the preference of one of the two elements for one of the two sites.
Print ISSN:
2194-4946
Electronic ISSN:
2196-7105
Topics:
Geosciences
,
Physics
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