ISSN:
1600-5724
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
When anomalous scatterers are present the electron density function is complex, both for centrosymmetric and non-centrosymmetric crystals. By neglecting Δf′′ in the calculation of the phase angles, the electron density map shows satellite maxima weighted according to Δf′′ in positions defined by combinations of interatomic vectors, as in Ramachandran's β general synthesis. On the other hand, when Δf′′ is accounted for, but the experimental data are not collected according to the point group symmetry, the electron density distribution calculated by the usual formulae shows maxima which are seriously affected both in position and shape. The errors are of the same type as those found in the least-squares refinement, when Δf′′ is neglected.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0567739472000142
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