Talk:Electron diffraction/GA2

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GA Review

Passed. FuzzyMagma (talk) 18:53, 20 November 2023 (UTC)[reply]

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

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Reviewer: FuzzyMagma (talk · contribs) 10:35, 27 October 2023 (UTC)[reply]

GA review – see WP:WIAGA for criteria

  1. Is it well written?
    A. The prose is clear and concise, and the spelling and grammar are correct:
    B. It complies with the manual of style guidelines for lead sections, layout, words to watch, fiction, and list incorporation:
  2. Is it verifiable with no original research?
    A. It contains a list of all references (sources of information), presented in accordance with the layout style guideline:
    B. Reliable sources are cited inline. All content that could reasonably be challenged, except for plot summaries and that which summarizes cited content elsewhere in the article, must be cited no later than the end of the paragraph (or line if the content is not in prose):
    C. It contains no original research:
    D. It contains no copyright violations nor plagiarism:
  3. Is it broad in its coverage?
    A. It addresses the main aspects of the topic:
    B. It stays focused on the topic without going into unnecessary detail (see summary style):
  4. Is it neutral?
    It represents viewpoints fairly and without editorial bias, giving due weight to each:
  5. Is it stable?
    It does not change significantly from day to day because of an ongoing edit war or content dispute:
  6. Is it illustrated, if possible, by images?
    A. Images are tagged with their copyright status, and valid non-free use rationales are provided for non-free content:
    B. Images are relevant to the topic, and have suitable captions:
  7. Overall:
    Pass or Fail:

Comments:

I can but feel that this work is a product of love. It is really well-thought and well-written. Most of my comments is to improve the text readability. I will add below some comments for improvement as I read through the text. Sadly I cannot edit the article directly during the review process as not to become an author. You can reply directly to each comment by just pressing reply.

  • Cowley, John Maxwell (1995). Diffraction physics. North-Holland personal library (3 ed.). Amsterdam New York: Elsevier Science B.V. ISBN 978-0-444-82218-5.
FuzzyMagma (talk) 11:58, 3 November 2023 (UTC)[reply]
Changed. checkY Ldm1954 (talk) 23:25, 7 November 2023 (UTC)[reply]

References spot checks:

  • Ref 8 (Low-Energy Electron Diffraction), 9 (Reflection high-energy electron diffraction), 108 (Practical Electron Microscopy in Materials Science), 113 (Falling Felines and Fundamental Physics), 115, 116, 117, 119, 121, 125, 147, 160 and 168: These are books. You need to include the page number as you did with the other books especially when it used more than once.
  • Ref 20 points to one page 183 and used 3 times only the 1st one check out
  • Ref 11.k: checks out
  • Ref 98: Checks out
  • Ref 102: checks out

FuzzyMagma (talk) 11:58, 3 November 2023 (UTC)[reply]

First, for the books, there are two classes of references:
1) Those where a specific point is being made which connects to some specific location in the text.
2) Those where it is general, and the whole book is relevant.
8, 9, 109, 116, 117, 119, 121, 147, 160 are all, deliberately, the whole book
113 was a citing glitch as the Book and Chapter are the same, corrected
115, 125, are from a prior editor, I will adjust tomorrow
You suggested 168, so please provide some page numbers! Ldm1954 (talk) 23:42, 7 November 2023 (UTC)[reply]
Nope! I need to be able to verify the information in order for this article to pass. As for 168, am not sure what you mean by “you suggested 168”. I do not remember doing that FuzzyMagma (talk) 23:48, 7 November 2023 (UTC)[reply]
Correction, you did not recommend 168. I will edit that tomorrow.
The "whole book" citations are correct. As an example, for 8 the wording is "it is a technique called LEED [8]", and the reference is a book that describes LEED. If I included page numbers they would be to the whole book, which would be inappropriate. Ldm1954 (talk) 00:10, 8 November 2023 (UTC)[reply]
I will ask for a second opinion although am sure I am correct FuzzyMagma (talk) 08:09, 8 November 2023 (UTC)[reply]
Please let me finish everything else first.
If a whole book is relevant then page numbers make no sense. As I said before, the reference is to LEED which is the topic of the book; page numbers 1-622 is identical to all pages, this is the standard short form. Please remember that common sense should always be applied, it is an accepted term. Ldm1954 (talk) 09:42, 8 November 2023 (UTC)[reply]
115 and 125 have been removed, it were inappropriate references from a prior editor of a weak earlier version.
168 has been cleaned up (not 166 with page numbers)
Pages corrected with 20
References are all done.checkY Ldm1954 (talk) 19:20, 8 November 2023 (UTC)[reply]
That list was not exhaustive btw although you also did not fix all of them, here in details from this version of the article you still have Ref 2, 8, 9, 59, 77, 86, 108, 113, 114, 115, 116, 117, 118, 119, 120, 133, 144, 159, and 167 FuzzyMagma (talk) 20:55, 8 November 2023 (UTC)[reply]
2,8,9,59,86, 114, 115, 118, 119, 120, 144, 159 are all books. They are correct as is.
Added for 77
113, 167 done before
There is nothing wrong with 133, it has page numbers
Delete 108, 116, 117 Ldm1954 (talk) 21:36, 8 November 2023 (UTC)[reply]
To be clear, let me give an example sentence:
"George wrote a textbook.[1]"
You don't do page numbers, the whole book is the reference. Ldm1954 (talk) 03:35, 9 November 2023 (UTC)[reply]
I really do not understand why are you saying that books are ok especially books you used more than once.
Pages needed for 2c, 8d, 9b & f, 59, 77, 86a & e, 108, 112, 113 a to d, 114, 115, 116, 117, 118, 119, 120, 133, 144, 156, and 167 FuzzyMagma (talk) 19:27, 9 November 2023 (UTC)[reply]
Sorry, for start you are incorrect about 112, it has pp 243–263 so the use of {{Rp}} is wrong.
I will give two more examples.
a) George wrote a book.[1]
b) As part of his book George describes a trip to Atlanta.[1]{{Rp}}
1. George's Book, published by ...
These are correct. In a) the source is the whole book, no pages. In b) it is necessary to include the pages which detail the trip.
You are incorrect about the references, they are all "a)" above. I won't go over all of them, just three examples with the quoted text:
"The normal usage in the field."[2] (which refers to 2c). The book is on TEM, which is the field. This is deliberate and correct; in some other locations I do use [2]{{Rp}} when b) is appropriate.
"Electron diffraction in a TEM exploits controlled electron beams using electron optics.[114]" and the book is on Electron Optics. It would be inappropriate to give page numbers.
"The main uses of RHEED to date have been during thin film growth,[156]", the title of the book is Applied RHEED : reflection high-energy electron diffraction during crystal growth. Ldm1954 (talk) 20:18, 9 November 2023 (UTC)[reply]
@Johnjbarton and @RoySmith: this one FuzzyMagma (talk) 08:49, 12 November 2023 (UTC)[reply]
I haven't been following this in detail, but the general rule is the citation needs to make it easy for the reader to verify the material. If you are citing a book, or even a chapter in a book longer than a couple of pages, you need to tell the reader exactly where to look, either by citing a specific page or short range of pages in the citation itself, or by augmenting the citation with additional location information via {{rp}} or something similar. Looking at the thread above, I'd say that "243–263" is a long enough span of pages that you really do need {{rp}} to narrow things down. RoySmith (talk) 11:48, 12 November 2023 (UTC)[reply]
Dear Roy, unfortunately that is not how science referencing works in general. Almost always articles contain background, experimental/theoretical methods and results all of which explain/justify certain conclusions. While there are a few exceptions, it is very rare to quote just a single page from a science article, it would be considered inappropriate. As one example, [16] is all about where to trace the source of elektron, detailing that it is wrong to just attribute it to Thales although many have.
With a book or book chapter, in journals the whole book/chapter is normally cited. Within Wikipedia it depends. For the book chapter [20] it is pages 83-86 because the rest is less relevant. In many cases I use the whole chapter from a book because it all has to be read, it is wrong to extract. Yes, that does mean that a reader has to read the whole chapter to verify/understand in detail. In a few cases I have included "field references", i.e. a whole topic, and these have no pages. To give an analogy, in general you would not select pages from a book if you are citing the field of Quantum Mechanics, you would cite the whole book. You can contrast this to a Chapter on the uncertainty principle, and perhaps a single page one when Schroedinger first published his equation. Ldm1954 (talk) 16:01, 12 November 2023 (UTC)[reply]
Just like the variation between different scientific journals, there is variation between how journals do things and how WP:GA does things. One might call it our house style. It would be presumptuous of me to claim that our way is better, but it is our way. And just like with journals, nobody is forcing you to follow their house style but by the same token nobody is forcing the journal to publish your paper.
In our house style, we differentiate between in-line citations and general references; this is explained in the introductory section of WP:Inline citation. It sounds like what you want to do is make the reference in question into a general reference placed in a bibliography section instead of trying to shoehorn it into the in-line citation format. RoySmith (talk) 16:24, 12 November 2023 (UTC)[reply]
I agree. The goals and audience for scientific references and for Wikipedia references are quite different. In Wikipedia references support text not being deleted. Full-book references make it too difficult for editors to verify text. Johnjbarton (talk) 16:54, 12 November 2023 (UTC)[reply]
I think the reference 2c is not useful as presented. The sentence is
  • The normal usage in the field is to collectively refer to both the scattering process and the maps of directions as electron diffraction, not differentiating the two.
The item of information here that a reader or editor may wish to learn more about is not "the field" but rather that "normal usage...collectively refer". Three references to books about "the field" are not helpful. One reference to a specific page would work, but as this is really more of an issue of "common knowledge" I think such a page may not be easily found. An alternative could be two references, one on scattering and one on maps-of-directions, each using the term "electron diffraction".
For the case
  • "Electron diffraction in a TEM exploits controlled electron beams using electron optics.[114]" and the book is on Electron Optics.
The item of information is "TEM, controlled beams" and the reference should be to a description of controlled beams for TEM. The words 'electron optics' could be wikilinked, but a text on electron optics is not useful for the item of information.
For the case
  • "The main uses of RHEED to date have been during thin film growth,[156]", the title of the book is Applied RHEED
Similarly the item of information is "main uses". The reference is specific to crystal growth. If the text actually says that it covers the main uses of RHEED, that page should be cited. Otherwise the current full book citation would be ok if the text instead said something like "RHEED has been applied to study thin film crystal growth", shifting the item of information to the topic of the book. Johnjbarton (talk) 16:26, 12 November 2023 (UTC)[reply]
placed the article on-hold for 2 weeks to allow for the reference problem to be fixed. ping me when you are done FuzzyMagma (talk) 18:46, 20 November 2023 (UTC)[reply]
I am done. Relevant page/Chapters are all included. Ldm1954 (talk) 18:49, 20 November 2023 (UTC)[reply]
then congrats. Thanks for your patience and the effort that you put to improve this article and Wikipedia coverage. Good luck and sorry if you felt that my comments were too much FuzzyMagma (talk) 18:51, 20 November 2023 (UTC)[reply]

Some drive-by comments by RoySmith

I've been asked to comment on a couple of specific issues in this review. Use these comments however you see fit. RoySmith (talk) 17:46, 10 November 2023 (UTC)[reply]

Regarding the lead, I agree it could include more material. In general, I think people tend to cram too much detail into leads, so I'm sympathetic to the view that "More is not always better". I don't think we need to be a slave to the numbers suggested by MOS:LEADLENGTH, but in this case, the lead is substantially shorter than suggested, so it's worth considering augmenting it.

To get a trivial point out the way quickly, the lead mentions studying the atomic structure of liquids, which as far as I can tell isn't talked about in the article.

I'm sensitive to the "Make the lead section accessible to as broad an audience as possible" requirement of MOS:INTRO so I agree that the more technical material in the article is not appropriate for the lead. It's hard to know what exactly constitutes a "broad audience". For a technical subject like this, I think it's fair to assume general knowlege about the subject. I'm not a physicist, but I did well in my physics courses in college (a long time ago) and I have kept up an interest in the subject. I'm currently working my way through the MIT Open Courseware videos on intro to quantum mechanics. So I think I'm a reasonable approximation to the intended definition of appropriately broad audience. With that out of the way, here's a bullet list of things I see in the article which could usefully be covered in the lead:

  • How the early work on CRTs led to an understanding of particle nature of the electron and an estimate of their mass.
  • How experiments in the early 20th century (Davisson–Germer, etc) led to the realization that the particle nature was an incomplete understanding.
  • How increasing understanding of electron diffraction led to advances in electron microscopy.
  • "Often combined with other methods"
  • "sometimes to solve an unknown crystal structure."
  • " TEM analysis ... can be used to obtain information from ... just a few or even single atoms."
  • Can be used to analyze quasi-crystals and aperiodic crystals.

This is not an exhaustive list, just some items I noted by reading through the article quickly. I think the bottom line is that there's certainly more topics which are mentioned in the article which could be mentioned in the lead without digging into excessively technical details. RoySmith (talk) 17:46, 10 November 2023 (UTC)[reply]

Thanks. I will add a little non-technical to the lead, and I agree with you it needs to be non-technical; I accept that JohnJBarton also suggests expanding the lead slightly, again non-technical. I will have to think, carefully how to do this cleanly. (There was a disagreement with FuzzyMagma on how technical it should be as you probably noted.)
N.B., there is nothing special about electron diffraction of liquids, they are put into a cell. It is just not that common, so not expanded upon. I will ponder deleting it as a digression that could confuse. Ldm1954 (talk) 03:54, 11 November 2023 (UTC)[reply]
If it's interesting enough to be called out in the lead, then it's interesting enough to be covered in the article body. And vice-versa. RoySmith (talk) 14:55, 11 November 2023 (UTC)[reply]
@RoySmith since you are here, can you please advise on the reference. The point just above your comment FuzzyMagma (talk) 18:32, 11 November 2023 (UTC)[reply]

Requested review

@FuzzyMagma asked me to review this article, I believe in an overall sense rather than in detail.

Broadly the article is fantastic with lots of interesting subtopics, images throughout, and an excellent coverage of relevant, mostly secondary references. My comments are only intended to help further improvement and not to detract from what I think should be a GA pass.

I agree with @FuzzyMagma that the introduction section does not represent the article. The outline of the article is clean and clear: History, Physics (called basics), Types and Techniques. But the intro is dominated by physics and some of that discussion does not even seem to be in the article. The article is strong on applications and has a solid history section. I think the lead should give a sense of the era (one sentence with dates for discovery and a couple of key technology introductions) and outline techniques/applications. To be specific, I would move the second paragraph into the body and replace it with the fourth paragraph of the Description (the paragraph with TEM, SEM, RHEED, LEED, etc).

I found the first sentence puzzling: it reads like a description of reflection or at most scattering. It certainly makes electron diffraction sound like a particle effect. This contrary to both the History and Description sections.

The Description section is essential a continuation of the introduction. So the introduction is too short but the combination is too long. Some of the Description material could go into the introduction paragraphs for the major outline sections. Again to be specific I would shoot for four paragraphs of introduction: lede, physics, history, and techniques, each a summary, not new material. Then I would disperse the remaining Description to the heads of sections.

To me the section "Basics" is "Physics". It's not a section on basic techniques for example, just about physics. Similarly the section "Types and Techniques" would be clearer and more interesting as "Techniques and Applications".

The "Electrons in a vacuum" is relevant to the applications section but not obviously essential for "electron diffraction". I suggest calling out the connection in the first sentence of the section. eg "The discovery of electron diffraction built upon a long history of scientific inquiry into "electricity" and "cathode rays" culminating in the discovery of the electron."

The sentence in the de Broglie section "He proposed that particles are bundles of waves (wave packets) that move with a group velocity and have an effective mass, see for instance Figure 4." needs a reference. As I read de Broglie's thesis he is very careful not to say anything beyond the wave being "associated". His derivation is based upon special relativity so he knows the meaning of wave packets is unclear. Heisenberg famously shows that Schrodinger's equation does not allow general interpretation as wave packets. The interference phenomenon of diffraction cannot be explained by wave packet on the size of electrons, so I don't understand why this sentence is even included.

The section heading "Further developments in methods and modelling" understates the impact of the work discussed. Maybe "Quantitative analysis"?

The section on "Geometrical considerations" is rather long and does not come across as geometry at the outset. I think this section would be much stronger if it started with a diffraction pattern and geometrical analysis, then plane waves. That would lead to discussing energy/wavelength issues in a separate subsection.

From here on the article enters very strong sections.

The article does not cover some kinds of electron diffraction, eg photon-induced electron diffraction. I think it would benefit from a bit more comparison to x-ray and neutron. These can be mentioned in future edits.

Hope this helps. Definitely a GA article IMO. Johnjbarton (talk) 16:51, 10 November 2023 (UTC)[reply]

A lot of good points John. Just a couple of quick responses, I will look more but I have a couple of papers to finish:
  • There is masses which is not covered, for instance Dynamical electron diffraction, Ultrafast electron diffraction, Photoelectron diffraction, Point source electron diffraction, Critical voltage effect, Borrmann effect (for electrons) etc and this list is not complete -- note the red. I tried to draw the line at those with thousands of papers.
  • I will cross-check de Broglie's thesis, but when I read it some months ago that idea was there, and I believed his thesis is already referenced. He did not talk about travelling wavepackets, rather as electrons around atoms as wavepackets. Of course this was before the formal math.
  • As I am sure John knows, there are stacks of papers/sites which claim that ED proved the de Broglie hypothesis, despite the fact that the papers say it did not as mentioned in the article. This kindoff wave matters.
  • The electrons in vacuum history part is background to microscopes, so IMHO it belongs.
  • The Further developments is both theory and experiment. I agree that it is an understatement, but that is somewhat the Wikipedia way.
  • Depending upon one's background, the Basics could be called Electron crystallography, Materials Science or Physics. (In the US TEM/TED is much more Materials Science than Physics.) Perhaps be neutral?
  • I will think about Geometry, although that is the standard terminology when talking about Ewald sphere and projection of the Reciprocal lattice. The approach I used is the same as in Cowley and most other texts.
  • The description section is supposed to be a gentle introduction to some key concepts for a high-school student.
  • John, in terms of direction please remember that in vacuum the wave-vector and group velocity are in the same direction. The first sentence is kinematical (plane wave), and ignores currrent flow which is way too specialized for the lead (and this article), and only matters with things like the Borrmann effect (for electrons).
  • I will look at a minor addition to the lead later, probably next week, but it has to be non-technical IMHO. I may have missed some of your points.
Ldm1954 (talk) 17:45, 10 November 2023 (UTC)[reply]
Since you have asked for the GA review, I encourage you to graciously accept more suggestions. For example, every reviewer has complained about the introduction. We are not asking for more technical content in the introduction. On the contrary I think the current introduction has too much detail. We are asking for the introduction to be an overall summary of the article, a more balanced overview. Johnjbarton (talk) 02:36, 11 November 2023 (UTC)[reply]
I will add a little so long as it is non technical, but it will take a week or so. Ldm1954 (talk) 03:43, 11 November 2023 (UTC)[reply]
Would you mind also having a look to reference issues outlined in the last comment of my review. FuzzyMagma (talk) 18:35, 11 November 2023 (UTC)[reply]
@Johnjbarton forgot to tag you FuzzyMagma (talk) 18:35, 11 November 2023 (UTC)[reply]
Sorry I'm unsure what you mean by "the last comment of my review". Can you edit in a pointer? Johnjbarton (talk) 02:27, 12 November 2023 (UTC)[reply]
The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.
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