Talk:Debye–Waller factor

The article still has serious problems.
 * The B-factor, or temperature factor, is defined in the PDB as $$ B = 8 \pi^2 \left\langle u^2 \right\rangle $$. This has units (of Angstrom^2 in the PDB) and is distinct from the DWF as defined in the article. Indeed, high quality = low uncertainty = low value of this B (as stated in the article), while obviously for the DWF as defined in the article, high quality ~ 1, low quality ~ 0. I don't seem to find references that clarify the different uses of the terms.
 * I have seen references that (in the terms of the above) $$ DWF = B \cdot \sin^2(\theta)/\lambda^2 $$. Using $$ q = 4 \pi \, \sin(\theta)/\lambda $$ this seems to give $$ DWF = q^2 \left\langle u^2 \right\rangle / 2 $$, while in the article it is explained why $$ DWF = q^2 \left\langle u^2 \right\rangle / 3 $$. So it seems there's also some mixup in the coefficients. — Preceding unsigned comment added by Schreib70 (talk • contribs) 16:15, 20 March 2011 (UTC)
 * It is simply not true that the magnitude of the B factors is an indicator of the quality of a structural model. It is an intrinsic property of the crystal.  You can have a very high-quality model for a structure that happens to have large B factors, just as you can have a lousy model for a structure that has low B factors.

Consequences
There should be something about consequences of the Debye-Waller factor here, for example that it suppresses peaks corresponding to high values of $$\mathbf{q}$$. This is obvious from the formula, but it should be mentioned because it actually explains why peaks in a typical $$I(2\theta)$$ spectrum become smaller from left to right and eventually disappear. --2A00:1398:9:FB01:120B:A9FF:FE22:BA68 (talk) 13:45, 14 November 2016 (UTC)

Derivation
A derivation from first principles would be nice. I studied this in school, but the article, as currently written, does not give enough to help me remember the details of the derivation. I mean... I can almost get it, but not quite. 67.198.37.17 (talk) 19:03, 4 July 2017 (UTC)