ISSN:
1600-5724
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
Direct methods are applied to the difference structure factors for a structure containing one or more heavy atoms in known positions. The present procedure is initiated by subtracting the known heavy-atom contribution from the observed structure factor (assuming that the observed and calculated structure factors have the same phase) to obtain the magnitude and phase of the light-atom contribution. The Σ2 phase relationship (tangent formula) is used to recalculate the phases of the light-atom contributions, and - consequently - to recalculate the magnitude of the light-atom contribution. An iterative procedure is used to optimize the phases and amplitudes before a difference Fourier map is calculated. The method is applicable also for the solution of partially known structures.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0567739476012321
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