Template:Did you know nominations/Spectral line shape

Clarity of article in question

Spectral line shape

 * ... that Lorentzian, Gaussian and Voigt functions are ideal spectral line shape functions?
 * ALT1 ... that most spectral line shapes are combination of two basic shapes, Lorentzian and Gaussian?
 * Reviewed: Ossicle

Created by Petergans (talk). Self nominated at 08:03, 2 May 2013 (UTC).


 * Symbol question.svg I couldn't confirm the hook. Online, the 3rd edition of Hollas only had a snippet view; the 4th has a preview, but a search on "Voigt" turned up nothing. Also "ideal function" is vague. RockMagnetist (talk) 15:56, 13 May 2013 (UTC)
 * Overall, the article is well written and well sourced, and is potentially interesting, but many readers will probably be put off by the organization. Arguably the heart of the article is the set of three ideal line shapes, but these are presented as unmotivated definitions. If you hunt through the article, you can start to get a sense of why spectroscopists are using them. For the Lorentzian, "This follows because the Fourier transform of the exponential function that is measured in the time domain is a Lorentzian where the spectrum is observed, in the frequency domain." (So halfway through the article we finally find out that spectra are in the frequency domain.) The Gaussian function, apparently, has something to do with the Maxwell-Boltzmann distribution; and the Voigt profile is the result of convolution when two broadening effects are combined.
 * The article badly needs a proper introduction that describes what a spectrum is how it is measured (here is where concepts like FWHM should be introduced); and then says a little about the general type of process that gives rise to each ideal line shape. RockMagnetist (talk) 16:32, 13 May 2013 (UTC)
 * In one of the notes, "It is unfortunate that use of the term deconvolution has become acceptable where the term that should be used is decomposition, resolution or fitting" violates WP:NPOV. Perhaps you can find a source for this judgement (see WP:SUBSTANTIATE). RockMagnetist (talk) 16:41, 13 May 2013 (UTC)
 * OK, I found it difficult to sequence the material. It's a chicken and egg situation as both "Definitions" and "Instances" depend on each other. I'll have a think about it.
 * Either way, a general introduction describing spectra shouldn't be a problem. RockMagnetist (talk) 17:20, 13 May 2013 (UTC)
 * Regarding the POV, there is no denying the fact that deconvolution is widely used for curve fitting and that deconvolution is a different mathematical process from curve fitting. The only POV is the word unfortunate, but I don't want to state that the term deconvolution is used without noting that this usage of the term is mathematically incorrect. That's not my opinion. It's a fact. Petergans (talk) 17:06, 13 May 2013 (UTC)
 * Ideally, you'll need some reference stating the relationship between the two uses of the term. Otherwise, it may be better to make a more neutral statement that avoids words like "incorrect" and states that in mathematics, deconvolution means something different. You'll still need a citation, though. RockMagnetist (talk) 17:20, 13 May 2013 (UTC)
 * All revised. I'd like to keep "ideal" as it contasts with "Actual" in the following sentence. Petergans (talk) 18:05, 13 May 2013 (UTC)

My original concerns about the hook were never addressed. This article is a good contribution, and I had hoped to find a way to pass it, but I have been finding a multitude of problems in style, grammar, organization and content. I have fixed some of the easier ones, but this is too big a job. The presentation of the line shapes is unmotivated, with no discussion of the context (i.e., absorption and emission spectra) or of the basic point that the line shape mainly depends on whether the broadening effects are homogeneous or inhomogeneous. I have added several sources that would help with the latter topic. Without a proper introduction, it is hard to understand the discussions of applications; and even then some parts would be unclear. For example, I have read the section on deconvolution a few times and I still have no idea why this process can "apparently improve spectral resolution." RockMagnetist (talk) 17:28, 27 May 2013 (UTC)
 * Symbol redirect vote 4.svg  What's going on here? Need a review. — Crisco 1492 (talk) 01:02, 27 May 2013 (UTC)
 * (after ec) I agree with RockMagnetist that the article could do with a better introduction. At the very least it could link to spectral line and give a brief def of what that is.  In fact, after looking at that article, I am not so sure it is not covering much the same ground and isn't a case for merging.  If not an outright merge, spectral line should at least have a main somewhere and make clear what the division between the two article's coverage is.  The article is also not as fully referenced as DYK likes to see nowadays.  I don't consider that a serious problem is this case though, most of the unreferenced material is describing well known mathematical functions.  Spinning  Spark  17:41, 27 May 2013 (UTC)
 * Hollas section 2.3 is devoted to line shape and broadening effects. (hook)
 * Reference to spectral line was intentionally limited as that article appears to deal only with atomic spectra.
 * Does this article meet DYK criteria? Decision, please. Petergans (talk) 07:52, 28 May 2013 (UTC)
 * I did make a decision - the symbol above means "no". However, I feel conflicted about this. The article might be good enough for DYK if a decent hook can be found. The proposed hook is of the "... that X is Y?" variety that is discouraged (see Did you know/Reviewing guide). I have added an example of a good hook (ALT1), but I don't think it is supported by the article. I think the structural problems that I have outlined above are the reason it is difficult to find a good hook. However, if another editor thinks I am asking too much of a DYK candidate, they can feel free to overrule me. RockMagnetist (talk) 22:38, 28 May 2013 (UTC)
 * The word "combination" in alt1 is a Weasel word and as such was not acceptable. The term "ideal" is used in the same sense as in ideal gas. The hook meets the guidelines above. Petergans (talk) 10:10, 29 May 2013 (UTC)
 * Symbol redirect vote 4.svg This article could use a review with a fresh pair of eyes, or else it should be removed from the nomination page due to inactivity and lack of consensus. -- Caponer (talk) 03:41, 18 June 2013 (UTC)
 * Ok, I have just had a look at this article, and my gut instinct (without a full review) is as follows:
 * the article is DYK-worthy, but needs more explanation - I am a chemist and understand the area but technicality makes it inaccessible to the average reader
 * the hooks are uninteresting and a new hook is needed
 * the artictle does not make clear the most important application of deconvolution... we need to understand line shapes to study overlapping spectral features so as to understand structure and properties of molecules (at the simple end of IR or NMR, say) up to macro structures like in MRI. I think readers are much more likely to be interested in the applications that a knowledge of spectral line shapes allows than in the mathematical models use, hence a hook like:
 * ... that studying the spectral line shapes of molecules allows scientists to determine the composition of stars?
 * ... that studying spectral line shapes is used in stellar chemistry to determine the chemistry of outer space?
 * ... that gadolinium-based pharmaceuticals alter spectral line shapes in magnetic resonance imaging allowing better visualisation of some brain tumours?
 * I realise these need additions to the article, but they are true and would be much better hooks. This last hook could be illustrated with a picture like the one here.
 * Thoughts? EdChem (talk) 00:34, 19 June 2013 (UTC)
 * It doesn't matter that they are true. Uninteresting is unimportant. The hook must be in the article, and properly referenced. Hawkeye7 (talk) 20:07, 20 June 2013 (UTC)

Thanks for these great suggestions. I've just returned from a conference in Spain and will look to revising the article and hook in the next day or two. Petergans (talk) 09:24, 22 June 2013 (UTC)


 * Accept hook
 * ... that gadolinium-based pharmaceuticals alter spectral line shapes in magnetic resonance imaging allowing better visualisation of some brain tumours?
 * Lead and content modified. Petergans (talk) 08:52, 23 June 2013 (UTC)


 * Symbol question.svg I cannot pass the proposed hook about gadolinium. I looked at the Google Books online preview of the book that's cited. I can't actually read the chapter ("Relaxation") that is identified in the citation, but neither the table of contents nor the search results that I can see (for "gadolinium", "spectral line shape", "spectral line", and "brain") nor the book's index so much as hints that the chapter might contain the kind of content that would include this hook fact. Gadolinium-based contrast agents are discussed much later in the book; in those later sections I do see extensive discussion of the value of this kind of imaging for investigation of several kinds of tumors, but I don't see mention of brain tumors.
 * Also, I noted that the hook fact was added to the article lead section. I removed it, but edited the article body to include the substance that I had removed from the lead. This is a detail that is not sufficiently important to the topic to belong in the article lead section, which is supposed to summarize the rest of the article. There is no requirement that a DYK hook appear in the article lead. --Orlady (talk) 02:32, 26 June 2013 (UTC)
 * How about


 * .. that spectral line shapes are needed in many types of spectroscopy for curve fitting of spectra containing overlapping lines.
 * Unfortunately, reference 6 (Maddams) is in a journal that does not give DOI, but the abstract (https://www.s-a-s.org/journal/viewer/abstract/1256/) explicitly mentions "shape". Petergans (talk) 08:03, 26 June 2013 (UTC)
 * Symbol question.svg seems to be a good deal of confusion in this submsission over what the requirements for DYK actually are. Firstly, the hook fact must be in the article.  It is not enough that it could be synthesised from the article text, it must actually be there saying more or less the same thing as the hook.  There are three places that the Maddams source is cited, but at none of those places in the article are "many types" or "overlapping lines" mentioned.  Secondly, there must be an inline citation where the hook fact appears in the article that directly verifies the fact.  In most cases we would expect the cite to include a specific page number where the verification could be found.  Citing entire journal articles or book chapters is not usually considered sufficient (unless the entire article/chapter/book/webpage is about the hook fact).
 * It is not necessary that the source cited be freely available online. We normally assume good faith for offline and behind paywall sources unless there is evidence to the contrary.  However, given that several hook submissions in this submission have failed verification already, it would be wise to post the exact quote from the source which verifies the hook, either on this page or in the footnotes for the article.  Spinning  Spark  10:27, 26 June 2013 (UTC)


 * Symbol delete vote.svg Regardless of whether a suitably cited hook is found in the discussion above, I cannot support this article going to the front page after the proposer's refusal to clarify in-article the relationship of spectral line and spectral line shape. The argument that spectral line is not mentioned because it is not a broad enough article speaks for the need to expand that article, not create another one.  The broadest article should be at the broadest title, not a more specific title.  That's not to say that I believe this article should not exist, but it needs to be placed in proper context with the rest of the encyclopaedia.  Deliberately wanting to isolate from other articles raises suspicions of WP:content forks and WP:walled gardens.  Spinning  Spark  10:27, 26 June 2013 (UTC)