ISSN:
1399-0047
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
The chemical, physical and symmetry constraints of an electron-density map impose relationships between structure factors, and these relationships are exploited during refinement. However, constraints often allow an artificially high correlation between the model and the original structure factors, a flaw known as model or refinement bias. Elimination of the bias component of a constrained model, the component insensitive to constraints, enhances the power of phase-refinement techniques. The scale of the bias component, here denoted as γ, is shown to be equal in magnitude to the origin vector of the interference function G that defines the relationships between the structure factors. The γ correction leads to solvent flipping in the case of phase improvement by solvent flattening, and other types of constraint allow a similar treatment.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0907444996015272
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