Talk:Bragg diffraction

Brillouin zones

Question for Drxenocide: I am a bit uncomfortable with the short explanation of Brillouin zones. Is this required? Does it add to a person's understanding of Bragg diffraction? The key here being diffraction. Can you explain why someone who wants to learn about diffraction should also understand these zones? If so, I will work to clean up the grammar and expand the subsection a bit. But I am much more inclined to delete the reference at the moment. What do others think?

-S.N. Hillbrand 19:58, 30 Apr 2005 (UTC)

I agree, the explanation of Brillouin zones is confusing rather than clarifying. I'd prefer deleting this part, and instead inserting a link in the "see also" section to the article on Brilloun zones. Furthermore, I'm uncertain if figs. 1a and 1b should be included here. I would much rather focus more on the derivation of the Bragg equation and figure 2.

-Prytz 18:55, 12 November 2005 (UTC)

The current wording is somewhat tangential and confusing, but I don't think it's completely out of place. It would certainly be useful to note the equivalence between the Bragg planes and the Brillouin zone boundaries, as these two qualifications (of a wavevectors lying on a "Brillouin zone boundary" or on a "Bragg plane") are often used interchangably in textbooks. Furthermore, the graphics I believe are quite relevant, though the actual connection to the Bragg formulation isn't made very clear.

-- Deklund 08:51, 20 November 2005 (UTC)

Ok, but what if we move that discussion to a separate section with its own heading, and maybe with a link to the Brilloun zone article. Preferably, this section should be placed after a brief discussion of the Bragg equation (which could include a more detailed derivation of the equation, if that's not to advanced for this text).

-O. Prytz 20:31, 20 November 2005 (UTC)

That sounds good to me. I don't think a more detailed derivation is too advanced for this article (though we should also provide a more basic explanation that anyone can understand relatively easily). It'd also be nice to present the equivalence between the Bragg formulation and other formulations of X-ray diffraction (the Von Laue formulation in particular). A discussion of the various methods of using X-ray diffraction to produce Bragg peaks (Laue method, rotating-crystal method, powder method) should also be discussed somewhere, but that may be more relevant in the X-ray crystallography article. So really this article could use a lot of work.

-Deklund 21:46, 20 November 2005 (UTC)

Yes, I agree. We should mention the von Laue formulation. The discussion of the different experimental setups for X-ray diffraction should be included in the X-ray crystallography article, although I won't be able to contribute much there. I'm an electron microscopist and have only limited experience with XRD. I'll be too busy to do any updates the next week or so, you go right ahead if you want to. Otherwise, I'll start looking into it in a couple of weeks time. I'm also wotking on the electron diffraction article, maybe you have something to contribute here? In general, I'd like an article tying together different diffraction techniques (X-rays, electrons, neutrons) with som details on the scattering mechanisms involved. For example a discussion of scattering by Coulombic forces for electrons, nuclear forces and magnetism for neutrons and so on... Big project though...

-O. Prytz 10:04, 24 November 2005 (UTC)

I tried to incorporate some of the suggestions into the article. There are a couple of points where it could use some more diagrams (I'm sure several people will be scratching their heads over the "plane that is the perpendicular bisector to a reciprocal lattice vector G lying at the origin of k-space"). I mentioned in passing the Brillouin zones without really defining them; anyone who cares to know can click the link and read the article. I'm not as familiar with the experimental side of either X-ray or electron diffraction, so I don't know how much I can help there.

-Deklund 02:52, 2 December 2005 (UTC)

Agreed. Though important, the reciprocal lattice isn't required at all to solve Bragg diffraction problems. Therefore, it's something of an accessory. It's definitely worth linking to though, as a great many students will be introduced to this topic via the reciprocal lattice formulation.

Sojourner001 18:31, 18 January 2007 (UTC)

I hesitate to speak up here, as I'm by no means qualified but is there a mistake in the paragraph "Bragg Condition" - the article gives path difference as "2dsinθ, where θ is the scattering angle." - I think in this case θ is the Bragg Angle, which is half the scattering angle. Would someone more authoritative care to comment and make a correction if I'm right? - I have no idea of the correct etiquette or practice of making such changes.

Question

I have an assignment to write about photonic crystals, and I keep seeing different definitions of what bragg reflection/diffraction/scattering actually is. The two main concepts are 1) electromagnetic (EM) waves (with a certain wavelength) that hit a material consisting of layers of alternating refractive index, will be (totally) reflected, 2) photons/electrons/etc. scatter against the atom layers, and you get constructive/destructive interference depending on the wavelength and angle of the incoming wave. Could someone enlighten me on this? I might have this all wrong, so please correct me if so!

FSund (talk) 15:52, 2 March 2011 (UTC)

Merge into Bragg's law

Please see the following discussion on the recent (undiscussed) merge of this article into Bragg's law: Talk:Bragg's_law#Merge_from_Bragg_diffraction. Polyamorph (talk) 07:46, 29 March 2011 (UTC)