On integrating the techniques of direct methods with anomalous dispersion. III. Estimation of two-wavelength two-phase structure invariants.
For diffraction data at two wavelengths from a crystal with anomalous scatterers, there are six types of two-phase structure invariants for Friedel pairs. Two of the six are single-wavelength invariants; the other four are mixed-wavelength invariants. It is shown that the latter can be estimated by a straightforward extension of results from the probabilistic direct-methods theory for the single-wavelength anomalous scattering case described in paper I [Hauptman (1982). Acta Cryst. A38, 632-641]. Statistical tests of the mixed-wavelength estimates are reported for small-molecule and macro-molecular examples.
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Medical Foundation of Buffalo, Inc., NY 14203.
Blessing
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D008433:Mathematics; D015394:Molecular Structure; D014961:X-Ray Diffraction