Talk:Multi-wavelength anomalous diffraction

MAD vs SIRAS?
As I understand it, the description in the first paragraph "where two crystal structures exist -- one structure for which one or more atoms has been replaced by heavy-atoms" is wrong: if there are two structures (crystals) in one of which light atom(s) has been replaced by heavy anomalous scatterers, that involves Isomorphous Replacement. The particular scenario described would be called SIRAS - single isomorphous replacement with Anomalous Scattering. MAD involves a single crystal with anomalous scatterers, which may have been prepared by soaking a native crystal with heavy atom, but if so the native crystal is not used. In the case of "native mad" there is no replacement at all- a naturally ocurring anomalous scatterer such as iron in a heme or ironsulfur cluster provides the anomalous signal. The description was more accurate before the revision of 31 July 2011. Eaberry (talk) 06:00, 19 April 2012 (UTC)[reply]

There is a great deal wrong with this article. The biggest problem is the TITLE which I don't know how to change. "Multi-wavelength anomalous dispersion" is wrong, and "single-wavelength anomalous dispersion" is wrong, wrong, wrong!

"Dispersion", by definition, refers to the change of a property over an energy range. Hence, "dispersive" differences are measured between diffraction intensities acquired at the *different* energies of a MAD experiment. But MAD also makes use of "anomalous" differences - the intensity differences between Bijvoet mate reflections at the *same* wavelength for each energy of the MAD experiment. MAD makes use of BOTH dispersive and anomalous measurements. Thus MAD = Multi-wavelength Anomalous DIFFRACTION, not "dispersion". ("Single wavelength anomalous dispersion" is literally an oxymoron. By definition, there is no dispersion at a single wavelength!)

Please, someone with Wikipedia knowledge: Change the title of this entry to "Multi-wavelength Anomalous Diffraction"

(and while you're at it, please change the other dispersion nonsense to "Single-wavelength Anomalous Diffraction". — Preceding unsigned comment added by LawrenceShapiro Biochemist (talk • contribs) 02:59, 13 June 2012 (UTC)[reply]

I really don't think Karle was awarded the Nobel Prize for his work on anomalous phasing. This came late in his career. He was awarded the prize for his contributions to Direct Methods of crystal structure solution. — Preceding unsigned comment added by 130.246.132.178 (talk) 12:48, 2 July 2014 (UTC)[reply]

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