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Stock post message.svg To-do list for Spectroscopy: edit·history·watch·refresh· Updated 2004-08-09

  • Restructure according to guidelines in Wikipedia:WikiProject Science, ie. :
    • start with 2 or 3 paragraphs for the general public, using daily life examples
    • explain the applications of spectroscopy. In particular, explain its importance in the development of physics and many other sciences
    • present the different techniques and their classifications
    • detail the history
Priority 2


This section does not belong here. It is blatently commercial, gives no details concerning the algorithm and is unclear, to say the least, as to what it does and when it can be applied. It is much too specialised to be in an article which introduces a very broad range of techniquesPetergans 10:23, 24 March 2007 (UTC)

I agree absolutely. Unless there is disagreement, I will remove this section (perhaps to a separate article) in 48 hours. Ignoramibus 23:58, 23 April 2007 (UTC)

Mass spectroscopyEdit

Mass spectra don't really fit into this definition of spectrosopy. Is this a problem?

On the surface, it would seem so. But, according to Einstein's famous identity, E=mc^2, mass and energy are the same thing. one could, in principle, plot a mass spectrum in energy units rather than in mass units. That this is not done in practice does not overshadow the interchangeability of the units. Particle physicists, for instance, do you energy-derived units as a measure of mass--speaking of how many electron-volts a particle masses, for instance.

Mass spectroscopy is significantly different from the other spectrometers on the page. MS measures the deflection, dependant on mass, of ions in a magnetic field. The plots are of discrete ion-mass (the deflection), against how many of the corresponding atoms are present in the sample (intensity). You couldn't legimately ever put MS results in to an energy/frequency graph. I think it should be treated as an exception. -- sodium

The main difference between mass spectroscopy and the other the types described in the page is that MS is not light spectroscopy. It doesnt involve energy transitions between different quantum states.

Mass Spectrometry is not spectroscopy becuase it is not based on the physical principles of light-matter interactions. Stephen (talk) 17:17, 14 June 2009 (UTC)

Then mass spec should be prominently distinguished, probably in the header, because this is a perennial source of confusion. -kslays (talkcontribs) 19:11, 27 December 2010 (UTC)


I've made an attempt to make the haphazard list of examples a bit more structured, but I'm still not completely happy with the result. Ideally, the words in the name of a branch (e.g., X-ray electron spectroscopy), should each fit under one of the four classification schemes. However, in this example, X-ray refers to the frequency parameter AND the measurement process and electron refers to the measurable quantity AND the physical process. Merging into two general classifications does not work, because 'Fourier transform spectroscopy' wouldn't fit.

I'm not sure either that it was a good idea to move everything under electromagnetic spectroscopy to a separate page.

Any suggestions? -- Hankwang 19:03, 17 Mar 2004 (UTC)

Your new classification scheme for spectroscopy isnt dichotomizing very well. Im considering reverting, but it would be better if you could clean it up. Bensaccount 02:49, 22 Mar 2004 (UTC)

There is no mention of the spectroscopy of light reflected from a surface (eg of a planet, moon or asteroid) or of how this can be used to determine the chemical composition of the surface. --Tediouspedant (talk) 20:24, 2 October 2009 (UTC)


It is not necessary to include the history of spectra on this page. Bensaccount 02:32, 22 Mar 2004 (UTC)

Maybe a history is too much, but according to Wikipedia:The_perfect_article, an article should have an introduction that is comprehensible to nonspecialists without having to look up other articles. I quote:
The perfect Wikipedia article ...begins with a definition or clear description of the subject at hand. This is made as absolutely clear to the nonspecialist as the subject matter itself will allow. ... does not leave essential terminology unexplained, even within the article itself. If some piece of terminology is essential to the subject itself, then it should be explained in the article about that subject, even if it is also explained on another page as well.
The current introduction is too short. -- Hankwang 13:30, 22 Mar 2004 (UTC)

I agree, the introduction is too short but also inaccurate. It describes spectrometry independent of electromagnetic references and then goes on to define it again with reference to "light!" It should be one or the other, or the distinction should be more clear! I think one section for EM spectroscopy and another for "other" types would make things far more clear and "comprehensible to nonspecialists", regardless of exact definitions. Also considering the bulk of the material here (and elsewhere) concerns EM spectroscopy, it would make more sense to me. Biledemon 14:40, 12 July 2006 (UTC)


My wife, a biochem major, was looking for a definition of SPR spectroscopy here, but didn't find one. Is it under a different name, or does it need to be added to the article? Jwrosenzweig 01:32, 9 Mar 2005 (UTC)

Redirect Emission Spectroscopy to Photoemission spectroscopy?Edit

Should the newly inserted link to Emission Spectroscopy be redirected to the Photoemission spectroscopy article ? H Padleckas 04:27, 14 Jun 2005 (UTC)

I just made Emission Spectroscopy redirect to Emission spectrum#Emission spectroscopy, since Emission spectroscopy already goes there; note difference in lower and upper case S. H Padleckas (talk) 20:24, 31 December 2010 (UTC)

Thermal spectral smear?Edit

If a substance is sufficiently hot, will the thermal-kinetic energy of its component atoms smear out its spectral lines? However, according to Boltzmann_distribution#typical speed, a gas would have to be circa 1e15 K for this to be a significant problem, at which point the gas will not be an ideal gas. CS Miller 19:25, July 13, 2005 (UTC)

Atomic Absorption SpectroscopyEdit

"Atomic absorption spectroscopy (often called AA)"

I would've thought that atomic absorption spectroscopy was often called AAS, not AA.


The acronym AAS has also been used for atomic absorption spectroscopy. H Padleckas 06:51, 25 December 2005 (UTC)

WikiProject SpectroscopyEdit

I just started a new project for Spectroscopy. Please contribute if interested. --Tjr9898 04:00, 21 July 2006 (UTC)


I feel that the definition of spectroscopy is too narrrow. Spectroscopy is a very broad topic, so I think the introduction should concentrate on embracing this, and not on narrowing the definition.

Further, if we list all of the things that are called spectroscopy, then the definition should fit them all.

Perhaps it could be something along the lines of: Spectroscopy is the observation of the properties of light, matter and wavelike phenomena. -- 02:18, 16 October 2006 (UTC)

Please feel free to be bold and to make edits that you believe will improve the article!
Atlant 13:25, 16 October 2006 (UTC)


The issue of spectroscopy versus spectrometry has come up in several places. I think that wikipedia needs a definition of spectrometry. This could be a short article or incorporated into this one. There are many spectroscopic techniques that have spectrometric variants but there are also spectrometric techniques that are not spectroscopic at all, such as mass spectrometry. I fully expect this to be a difficult and confusing issue for editors and potentially an issue of debate but I think that readers are equally as confused. By the way what is here in terms of a definition is pretty good but too brief and hidden. I would suggest a short article and a smaller section here with a link to it. When the spectrometric variants are discussed here they should be designated as a form of spectrometry but that derives from spectroscopic phenomena. Of course there are many problems distinguishing between these since scientists have not always done a good job of distinguishing and maintaining internally consistent definitions. There will be some cases where there is overlap or cases where a spectrometric technique is named as a spectroscopic technique etc. In these cases we will need to have strong links between these two articles and address the subtleties and misnomers without defying current usage and consensus. I thought I should get some input here before being too bold.--Nick Y. 18:46, 14 December 2006 (UTC)


The main image of this article is probably soon deleted from Commons, as it is licensed under a NC license. Bryan 20:35, 30 January 2007 (UTC)


This information was taken excised from the article. It is placed here in case some of it deserves to be readded to this or another article. Srnec 22:44, 5 April 2007 (UTC)

Impedance spectroscopy is a study of frequency response in alternating current.

  • Absorption spectroscopy uses the range of electromagnetic spectra in which a substance absorbs. In atomic absorption spectroscopy, the sample is atomized and then light of a particular frequency is passed through the vapour. After calibration, the amount of absorption can be related to the concentrations of various metal ions through the Beer-Lambert law. The method can be automated and is widely used to measure concentrations of ions such as sodium and calcium in blood. Other types of spectroscopy may not require sample atomization. For example, ultraviolet/visible (UV/ Vis) absorption spectroscopy is most often performed on liquid samples to detect molecular content and infrared (IR) spectroscopy is most often performed on liquid, semi-liquid (paste,grease,and petroleum jelly), dried, or solid samples to determine molecular information, including structural information.
  • Emission spectroscopy uses the range of electromagnetic spectra in which a substance radiates. The substance first absorbs energy and then radiates this energy as light. This energy can be from a variety of sources, including collision (either due to high temperatures or otherwise), and chemical reactions.
  • Scattering spectroscopy measures certain physical properties by measuring the amount of light that a substance scatters at certain wavelengths, incident angles, and polarization angles. Scattering spectroscopy differs from emission spectroscopy due to the fact that the scattering process is much faster than the absorption/emission process. One of the most useful applications of light scattering spectroscopy is Raman spectroscopy.

Joseph von FraunhoferEdit

There should be some information on Joseph von Fraunhofer in this article.

Yes, I agree. There should be a "History" section mentioning him at the beginning. Normally, I'm not a big fan of necessarily putting a "History" section in every Wikipedia article, but this article should have one, at least an elementary one. These days, there's a lot more to spectroscopy than the spectroscope he invented, but we should start with there. I think etymology of spectroscopy and related words should be covered. H Padleckas (talk) 20:15, 31 December 2010 (UTC)

Inaccuracy of the articleEdit

I think the excision of a whole bunch of spectroscopic techniques is severely at odds with what spectroscopy is commonly taken to mean as is the 'definition' that the article gives. That definition must have been taken from a 1911 encyclopdia or so? At any rate it makes the article scientifically misleading and incorrect

In modern science spectroscopy can refer to any measurement performed where wavelength or frequency are systematically varied.

Jcwf (talk) 00:19, 14 January 2008 (UTC)

Circular DichroismEdit

There are good articles on circular dichroism and magnetic circular dichroism. Is there a reason they are not included in the types of spectroscopy or in the list at the end? Woops, circular dichroism is mentioned. Should magnetic be mentioned? It is similar, but has very distinct applications. BobertWABC (talk) 22:39, 4 March 2008 (UTC)

Same Periodic GroupEdit

Would elements in the same groups on the periodic table (for example: Copper, Silver, and Gold) have similar frequencies of absorption and emission?JeepAssembler (talk) 20:56, 18 September 2009 (UTC)JeepAssemblerJeepAssembler (talk) 20:56, 18 September 2009 (UTC)

Not exactly. H Padleckas (talk) 06:34, 22 January 2010 (UTC)


Spectrometry is here defined as being 'used to assess the concentration or amount of a given species'.

A species of what? Clearly not a biological species. Is species even the correct term to use here? It appears also at the end of the article, though as 'atomic or molecular species' which is slightly clearer. Saktoth (talk) 03:17, 22 January 2010 (UTC)

How about chemical species ? H Padleckas (talk) 06:06, 22 January 2010 (UTC)
I edited the introductory section to say "chemical (atomic, molecular, or ionic) species." Species is as good a word as any to use in this very broad context. H Padleckas (talk) 06:28, 22 January 2010 (UTC)


The section on background is good as far as it goes, but it ignores some related issues. For instance, in absorption spectroscopy it is common to correct for baseline absorption by the solvent system. It should also be noted that the background a broadband detector is responding to can contain stray light at other wavelengths. --AJim (talk) 18:49, 21 April 2010 (UTC)

Lists and lists and listsEdit

Most of the article length is currently given over to lists of spectroscopic techniques. These lists are spread over three sections and are dealt with in several different ways. I'm tempted to alter these sections significantly, but since the article has developed this way over a long period, I wanted some feedback before implementing a change. My preference would be to use the classification of methods section to sort through a wide range of techniques in a somewhat systematic manner. Any details of a particular topic, though, would be reserved for that topic's page. The entire Common Types section would be cut. The Other Types section would be kept in order to list any additional types of spectroscopy that were not mentioned previously. The See Also section would be cleaned up to no longer include additional types. Is this going too far? This would remove a great deal of the page's current content? ronningt (talk) 02:14, 28 December 2010 (UTC)

I agree; the section organization is terrible. I have thought about reorganizing along the lines of an undergraduate text, for example Crouch, Stanley; Skoog, Douglas A. (2007). Principles of instrumental analysis. Australia: Thomson Brooks/Cole. ISBN 0-495-01201-7.CS1 maint: multiple names: authors list (link) This book splits it up into atomic (AAS, AES, ICP-MS, atomic X-ray) and molecular (UV-Vis, fluorescence, IR, Raman, NMR, molecular MS, surface techniques). The atomic section starts off with a discussion of basic spectroscopic instrumentation. This would skew the article toward analytical spectroscopy at the expense of physical, though. Overall, the article should be much more basic and specialized techniques should be moved to sub-articles (e.g. CARS to the Raman article, etc.). --Kkmurray (talk) 17:48, 30 December 2010 (UTC)
I agree that the article was far from perfect and that it needed some work. For example under the previous "Common Types" of spectroscopy section, parts of the "Visible" and "Ultraviolet" were written in an apparently obsolete and misleading way and needed to be combined into one "Ultraviolet-Visible spectroscopy" section and rewritten. I do not agree with taking certain sections out which User:Ronningt took out, particularly the entire "Common types" of spectroscopy section. Even with that entire section, the Spectroscopy article was only about 27000 bytes long, leaving adequate room for expansion of what should be a very key article in Wikipedia. Now since that section plus other content have been taken out, this key article is only about 18000 bytes long, leaving plenty of room to put important info from that section back in. I also note that ronningt added a "Scientists of note" list of 51 scientists names instead, after complaining about apparently too many lists of types of spectroscopy. Many of the scientists in that list were from roughly around 100 years ago or more. Right now, hardly anything is said about fluorescence spectroscopy, X-ray spectroscopy, X-ray fluorescence, flame spectroscopic methods, ultraviolet-visible spectroscopy, or infrared spectroscopy. I see nothing in the article about atomic absorption spectroscopy. These are some of the most important types of chemical analysis spectroscopy. The "Other types" list has a number of more unusual types of spectroscopy, however, without listing most of the important ones above. The "Flame technique" section that was taken out needs to be put back in somewhere in Wikipedia, either in this article or the Atomic spectroscopy article. H Padleckas (talk) 05:46, 2 January 2011 (UTC)
Thank you for the feedback and comments. I just made some changes to try and make the links to the common techniques more obvious. I agree that these are very important to highlight, and I tried to include every technique that had been in the Common Types section within the expanded Classification of methods section. I would like to see these Classification sections expanded as needed to encompass the most important categories. I'm hoping that the current framework can allow for that. I do feel like details on particular techniques, beyond about a one sentence description, would be best left to a page dedicated to that technique so that readers don't get bogged down trying to understand a particular implementation. I would really value further contributions from physicists and materials scientists; my background is chemistry, and I get the feeling that the whole page is still weighted towards chemical applications of spectroscopy. I'm not sure how valuable the Scientists of note section is. I have only added Nobel prize winners and a few obvious historical figures; I definitely agree it should be expanded to include more recent researchers. ronningt (talk) 19:07, 2 January 2011 (UTC)
This is a good start. Two brief comments, though. First, the list of scientists should be converted to a "History of spectroscopy" section (the 4th lead section paragraph makes a start at this). There should also be a very basic "Theory" section. See the NMR article for example. Also Astronomy --Kkmurray (talk) 00:22, 3 January 2011 (UTC)

spectroscopy is not just about lightEdit

spectroscopy is not just about light or (a bit wider) electromagnetic waves. So, I have changed definition. It is poor, I know. I hope somebody can do better. But do not go back, to wrong electromagnetic-centered definition. — Preceding unsigned comment added by Vniizht (talkcontribs) 03:46, 31 October 2011 (UTC)

The issue is maintaining balance and a neutral point of view. The definition of spectroscopy that is limited to electromagnetic radiation is the most generally accepted as evidenced by its use in the IUPAC Gold Book,[1] textbooks,[2] Wictionary,[3] etc. The broader definition that includes other effects beyond electromagnetic radiation (e.g. force spectroscopy) is not as widely accepted. The lead section as you have edited it gives undue weight to the minority view. It is good to include both views but it must be done with the appropriate balance. --Kkmurray (talk) 13:57, 31 October 2011 (UTC)
I restored the previous definition. I feel like the IUPAC definition and the original introduction gives sufficient weight to spectroscopy that is outside of electromagnetic waves. Are there specific examples of non-electromagnetic spectroscopy that you feel are not sufficiently represented in the article? ronningt (talk) 14:58, 31 October 2011 (UTC)

Article needs to be redone!Edit

The article is obsolete, is hijacked by optical spectroscopists and plainly useless for users. Definition is laughable, it does not even recognize that in most cases (including optical spectroscopy) the process of interest is not INTERACTION with “radiated energy”, but GENERATION of it. Who feels he is responsible for the article, who keeps in present unhealthy state? — Preceding unsigned comment added by Vniizht (talkcontribs) 19:08, 22 November 2011 (UTC)

I appreciate your interest in this article, but you need to strengthen your case for making a change. From your comments and your previous edits, I do not understand your objection or the direction of the change you intend. I'm happy to work with you to come to an agreement on phrasing or the inclusion of additional topics. I'd be happy to review examples, articles or books that would clarify the aspects you feel are missing. ronningt (talk) 17:23, 23 November 2011 (UTC)

OK. For beginning change definition. It sertanly should not be centered on "interaction", since "generation" is more important. Include mass spectrometry in definition. — Preceding unsigned comment added by Vniizht (talkcontribs) 01:14, 24 November 2011 (UTC)

I've been wondering whether the mass spectrometry question should be explicitly addressed in the article. From that article, and from the most recent IUPAC recommendations[4], referring to mass spectrometry as mass spectroscopy is no longer recommended. However, the term has a lot of history and should probably be explicitly address in the spectroscopy article. I'll try to find a natural place to do so.
Do you not feel that the term "interaction" encompasses "generation"? I prefer "interaction" because I feel it encompasses both generation and absorption, which is an important aspect of several forms of spectroscopy. "Interaction" also captures scattering which is, arguably, another form of generation but is not typically conceptualized that way. ronningt (talk) 14:13, 25 November 2011 (UTC)

I <3 spectroscopy and I'm going to make this article beautifulEdit

Since nobody has posted on talk page in... what 6 years?.. I don't know if anybody will see this.. buuut. I'm about to add tons of awesome stuff to this article.. .and to spectrometer — Preceding unsigned comment added by Popcrate (talkcontribs) 16:37, 1 February 2017 (UTC)

I'm excited to see another editor interested in the spectroscopy articles. I continue to watch and tweak these, but it has been a while since I was inspired to attempt a significant rework. If you have ideas that you'd like to discuss, I'm happy to be a sounding board. From looking at your recent edits, I have one question to consider and one concern. First, would the information you've added on Newton and Wollaston be more appropriate in the history of spectroscopy article? The top level spectroscopy article has to cover a lot, and so we have tried to include summary information here that links out to more in depth articles. Second, the two paragraphs you've added are direct quotes from the source. I'm glad that you provided good attribution for the source of this information. As discussed here, it is generally my goal to accurately summarize a source unless the source is so uniquely or well presented that it deserves to be quoted directly. I'm happy to keep the discussion going here or to start a broader discussion of how to improve the spectroscopy content on one of our user pages. ronningt (talk) 14:14, 5 February 2017 (UTC)
Question answer: Yes, it definitely would be more appropriate in the history section, and I share your concern about my edit for exactly the same reason. To the talk pages now, because otherwise the discussion will get incredibly confusing =) Popcrate (talk) 03:17, 17 February 2017 (UTC)

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Titanium dioxide food additive to powdered sugarEdit

It might be interesting and informative to add some commentary about how absorption and emission spectroscopy is utilized in food additives, such as the spectra of titanium dioxide (photo) which is added to powdered sugar for doughnuts due to the emission spectra which makes white powdered sugar adopt a "glow" attribute when added.

The use of such additives can be controversial (Dunkin doughnuts) but it is still a multi-billion dollar (globally) application of spectroscopy utilized in corporate science labs to make foods appealing and to acquire an economic advantage utilizing science -- and human behavioral psychology. SoftwareThing (talk) 18:59, 7 September 2018 (UTC)

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