MAD phasing - part 2

Karle/Hendrickson equations

The complete structure factor for an individual reflection h at wavelength lambda is:

Note that the normal scattering component of the anomalous scattering atoms appears in more than one place in this equation; it is included in 0FT(h), in 0FAk(h), and in the explicit terms 0fk. The reason for this is that we want to reformulate things in terms of the ratio of f' and f'' to 0f.

MAD phasing of Karle [1980] as formulated by Hendrickson [1985]

Now we will consider the simplest case, with only one type of anomalous scattering atom, and express the magnitude of measured intensity |F(lambda)(h)|**2 in terms of its components:
Note the important fact that all of the wavelength-dependence has been collected into the coefficients a(lambda), b(lambda), and c(lambda).

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Ethan A Merritt ©1995-2001/ / Biomolecular Structure Center at UW