Talk:Electron diffraction

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History Section revised

The 2022 History section had a number of major issues. Parts of it appear to have been copied verbatim from other Wikipedia pages, some major contributions were not mentioned, many of the links were inaccurate or broken.

The current version is based upon searching various sources which are quoted in the article. Whereas the 2022 version had 11 cites, the current one has 63. The current version:

Has a more general description of electrons in vacuum, with more accurate citations.
Puts the work of de Broglie and Schroedinger better into context, including a quote on this from de Broglie.
Provides credit to at least some of the founders of electron optics.
Provides more extensive cites to the issues about who invented the TEM, which is not straightforward. I have attempted to be unbiased.
Added the critical paper by Boersch on SAED.
Added a bit about LEED/RHEED
Added something about how ED was viewed for many years using a quote from John Cowley,
Added a bit about advances. I do not think this is the place for more.

N.B., There might be duplicate references. Ldm1954 (talk) 20:53, 18 February 2023 (UTC)[reply]

Just a note, the tidbit which in turn is connected to the observations of electrostatic charging by Thales of Miletus around 585 BCE. references this paper which says in its abstract "there is no basis to believe [Thales] discovered, carried out experiments on, or systematically observed electrostatic charging." I haven't read the paper; it just caught my attention as I was skimming the History section. Wanted to make sure it's as intended. Ajpolino (talk) 05:02, 28 February 2023 (UTC)[reply]

Ajpolino it's a tricky point, and I deliberately used the word connected rather than discovered. As Daniel Lacks indicates, there is no proof -- but then our records are incomplete. For certain Thales knew of Triboelectricity charging, and the source of electron is the Greek word for amber. There is a Greek stamp with him, charging and amber, and many cites with stronger connections.

Please feel free to wordsmith this is sentence, it is generally accepted color rather than being critical. Ldm1954 (talk) 09:51, 28 February 2023 (UTC)[reply]

Equations and vectors

Proper vector notation should be used when needed, I cannot tell which $r$ should be $\mathbf {r}$ and which $r.k$ should be replaced by $\mathbf {r} \cdot \mathbf {k}$ . ReyHahn (talk) 14:09, 27 April 2023 (UTC)[reply]

A good suggestion, done. Ldm1954 (talk) 20:14, 27 April 2023 (UTC)[reply]

Schrödinger's removal and other suggestions

Firstly, most moderm physics prefer to use $\hbar$ instead of the original Planck h. Is this not the case in electron diffraction? Also modern books use $2\pi /\lambda =k$ and not $1/\lambda =k$ again is this special convention?

Secondly I suggest that the picture of Schrödinger has to go, the article has too many pictures and that figure is not adding to anything, he is not even the most famous physicist related to this topic (Thompson would be better but still unnecessary). Also the Schrodinger photo is not even referenced like the rest. To not rewrite the figures names every time one figure is removed or moved down, we should use a reference template, see an example here: [[1]]. ReyHahn (talk) 22:32, 27 April 2023 (UTC)[reply]

To clarify:

Please see notes c & d: the text uses the crystallography convention, which is standard in electron diffraction, not the physics convention. Using the physics notation is inappropriate, sorry. (Real & reciprocal lattice conventions similarly differ, also in the note.)
With the crystallography convention it is $h$ , not $\hbar$ .
Thompson has no relevance to electron diffraction, similarly Einstein, Hertz...
All ED theory starts with the Schroedinger equation, using Bethe's approach, it is the foundation. The quote from de Broglie's thesis is meant to indicate this (without shouting), and note b points out that Davisson and Germer knew, please check the ref if needed (I did). The text also tries to indicates this without shouting. (The methods use either Bloch waves, a Green's function approach or tight-binding, similar to band structure, but this is a massive digression.)

While automatic numbering of Figures would be nice, that template would not make it easy to cross-reference images. In the text there is need to specifically refer to these for the different cases at different places in the text. For instance, the Ewald sphere results are very different for TED, RHEED & LEED. This needs to be mentioned in the geometry, but the Figures themselves belong with the relevant text.

Finally, electron diffraction (and imaging) is image oriented. An image to illustrate each and the relevant Ewald sphere is consistent with standard useage. I see no harm in the images.

Discussion is good, particularly input from outside the field. Ldm1954 (talk) 02:59, 28 April 2023 (UTC)[reply]

Thanks you for clarifying the convention with respect to hbar, it makes sense now. Regarding the template, I think it allows to call a figure several times. As for the figures themselves, I see no harm on having an illustrated article, I just would prefer it to not be over illustrated a photo of Schrödinger is not clarifying anything.--ReyHahn (talk) 12:18, 28 April 2023 (UTC)[reply]

OK. If you were unsure, then I need to explain the notation issue better. I suspect that just having a note is not enough, it needs to be more "see Note xyz" or similar. Some wordsmithing needed.

I will play with that template in my Sandbox "soon", to see if I can tweak it into something comparable to standard publication labelling. I will do that before reconsidering the image, which is admittedly not so critical. Ldm1954 (talk) 12:26, 28 April 2023 (UTC)[reply]

N.B., you don't like Brownies? A touch of humor is needed, let's not fall asleep with dryness. Ldm1954 (talk) 19:55, 28 April 2023 (UTC)[reply]

See WP:JOKE.--ReyHahn (talk) 12:08, 3 May 2023 (UTC)[reply]

Topic expert

User:Ldm1954 you may be a topic expert, BUT we still require references for any content that you add. Theroadislong (talk) 17:29, 13 May 2023 (UTC)[reply]

They are already there. Ldm1954 (talk) 17:35, 13 May 2023 (UTC)[reply]

You may consider it "pedantic", and tiresome, but it is absolutely required that all content is correctly sourced. Theroadislong (talk) 20:36, 13 May 2023 (UTC)[reply]

As you have yourself stated before, science is not your area. Therefore it is understandable that you do not realise that terms & content have already been sourced, often within a sentence. Your statements about lack of content sourcing are highly inappropriate. For instance, the book by Born and Wolf has extensive information on classic wave, aperture, Fresnel and Fraunhofer diffraction. Please stop making such comments, they are not constructive. Ldm1954 (talk) 20:50, 13 May 2023 (UTC)[reply]

Science is not my area but Wikipedia is, and correct sourcing is imperative per Wikipedia:5P2 which states that "all articles must strive for verifiable accuracy, citing reliable, authoritative sources." Theroadislong (talk) 20:59, 13 May 2023 (UTC)[reply]

To repeat, it was always there. Ldm1954 (talk) 21:05, 13 May 2023 (UTC)[reply]

@Theroadislong Is there some specific concerns you have? To me, this is a comprehensive article with a very large number of references and cross links. Johnjbarton (talk) 17:40, 16 May 2023 (UTC)[reply]

I was concerned that the editor was adding content and comments based on their knowledge of the topic rather than referencing the sources. Happy to be shown the error of my ways. Theroadislong (talk) 08:12, 18 May 2023 (UTC)[reply]

Proposed less steep intro text for Electron Diffraction

Please see User:Johnjbarton/Electron_Diffraction_Sandbox

This version drops the intro text "Close to the atoms the changes are described as Fresnel diffraction; far away they are called Fraunhofer diffraction. " IMO here is too early and it's covered later. Also drops the note as the intro covers naturally now.

Overall I was going for a positioning with linking that set expectations.

Please feel free to use, edit, or ignore as you like. Johnjbarton (talk) 01:27, 17 May 2023 (UTC)[reply]

I like the concept, and will use it with (perhaps) a few changes. Within a few days, I have some paperwork to do first. Ldm1954 (talk) 11:48, 18 May 2023 (UTC)[reply]