Talk:Luminescence

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--72.24.243.55 (talk) 23:23, 20 January 2015 (UTC) Current definition: "a general term for the emission of electromagnetic radiation at a different wavelength than that at which it is absorbed" is taken (slightly changed) from: http://scienceworld.wolfram.com/physics/Luminescence.html , but I think it's wrong. I've checked in a few other sources (eg. dict.org, Britannica), and lumincescence is only light emission (not any EM radiation) and nothing has to be absorbed (eg. in bioluminescence). Wojdyr 20:12, 29 July 2005 (UTC)[reply]

- This article should really mention that the mechanism of luminescence requires the release of a photon, which balances the energy of an electron jumping to a lower energy state (as in not a photon released in a nuclear reaction.)

- Get rid of subatomic motions as a source of luminescence, or get rid of everything other than that.

- The article contradicts itself when is contrasts luminescence with incandescence, and yet describes thermoluminescence.

- "Luminescence is light that usually occurs" is like a terrible phrase. —Preceding unsigned comment added by 67.242.102.134 (talk) 23:07, 4 May 2010 (UTC)[reply]

I know a bunch of phosphors which are excellent still at temperatures far above 1000°C. Of course temperature quenches optical transitions, but in fact it is also able to enhance luminescence (for example if at lower tempreature a certain barrier can not be passed, see e.g. the charge-transfer excitation in YVO_4:RE, where RE is Eu^3+, Dy^3+ or other trivalent rare earth ions).

Therefore i propose a different definition. Let's for example take Blasse and Grabmayer (Luminescent Materials, Springer 1994):

"A luminescent material ... is a solid which converts certain types of energy into electromagnetic radiation over and above thermal radiation". This simply means it is a conversion of energy into EM radiation by matter, excluding incandescence.--134.245.70.65 (talk) 13:24, 7 July 2010 (UTC)[reply]

I disagree with poster 67.242.102.134 when he states that the "The article contradicts itself when is contrasts luminescence with incandescence, and yet describes thermoluminescence." This is patently wrong. When one reads the article on thermoluminscence, it clearly explains that the phenomenon is characterized by release of photons in wavelengths not attributable to black body radiation.

I disagree with the proposed definition by poster 134.245.70.65. First, the material doesn't have to be a solid. "Over and above" is not good phrasing, IMO it should be "as distinct from." The statement is confusing as thermal radiation includes those wavelengths in which luminescence is observed, the difference is they are not caused by heat, but by other, distinct mechanisms. The current definition is much better than the to which this poster objects, but I wanted to get my criticisms to his points on record to avoid any future confusion. Brownwn (talk) 22:23, 10 October 2014 (UTC)maddie was here[reply]

Short description

Could we change the short description from "Spontaneous emission of light by a substance" to something like "light emitted from non-incandescent bodies"? TlonicChronic (talk) 20:14, 27 December 2023 (UTC)[reply]

Lead quote

@Kent Dominic: Please quote the relevant passage from WP:NOTADICTIONARY, because I see nothing that even remotely supports your claim that quotations need not be enqouted in the lead, or anywhere, for that matter. Paradoctor (talk) 08:19, 5 June 2024 (UTC)[reply]

From a semantic standpoint, putting quotation marks around the material in the lead gives the impression Wikipedia offers a specific luminescence definition that excludes other descriptions. As you probably know, however, Wikipedia is not a dictionary, and doesn't give undue weight to one source versus another.

My edit to the lede (as well as my other edits to the article) is mostly cosmetic in that regard. Substantively, I take considerable issue with lede's "electronically or vibrationally excited species" verbiage. Why? Semantically, that instance of electronically applies distributively to species, creating no small amount of equivocation since it's not fair to characterize a species as being electronic. Additionally, the current lede is limited to chemical luminescence as described by the International Union of Pure and Applied Chemistry. The general concept of luminescence is considerably broader than that.

The Encyclopedia Britannica gives, IMHO, a better description of luminescence as "emission of light by certain materials when they are relatively cool". That wording is more concise, absent the equivocation in the current lede, and more accessible to readers who are likely to want a simple description.

Nb: If you agree the lede needs wholesale change from the current verbiage, I'll be quick to reiterate that going with the Encyclopedia Britannica wording won't need quotation marks as it would be redundant to the required cite. Neither would there be need for quotation marks upon citing bioluminescence if the current lede's verbiage is worked into a subsection on that angle. Kent Dominic·(talk) 13:43, 5 June 2024 (UTC)[reply]

P.S. The "Short description" comment by TlonicChronic parallels my thinking on all of the above. Kent Dominic·(talk) 13:45, 5 June 2024 (UTC)[reply]

Are you even listening to yourself? Paradoctor (talk) 15:06, 5 June 2024 (UTC)[reply]

WP:FOC. Kent Dominic·(talk) 15:34, 5 June 2024 (UTC)[reply]

WP:CIR Paradoctor (talk) 15:45, 5 June 2024 (UTC)[reply]

I take considerable issue with lede's "electronically or vibrationally excited species" verbiage. Why? Semantically, that instance of electronically applies distributively to species, creating no small amount of equivocation since it's not fair to characterize a species as being electronic.

That instance of "electronically" applies to the excitation, not the species. "Fairness" hardly applies to inanimate mineral or chemical species. Just plain Bill (talk) 15:50, 5 June 2024 (UTC)[reply]

That instance of "electronically" applies to the excitation, not the species.

Your interpolation is correct, but that's not what the "Luminescence is a spontaneous emission of radiation from an electronically or vibrationally excited species" wording says. Accordingly, the ·wording should be "Luminescence is a spontaneous emission of radiation electronically or from a vibrationally excited species." Even more reason not to use a direct quote from the cited source.

"Fairness" hardly applies to inanimate mineral or chemical species.

Correction: I said "it's not fair to characterize a species as being electronic." I.e., an electronically... excited species isn't nonsense but it is equivocal. Kent Dominic·(talk) 10:42, 6 June 2024 (UTC)[reply]

wording should be "Luminescence is a spontaneous emission of radiation electronically or from a vibrationally excited species. Say what? That is meaningless ultracrepidarian word salad.

Feel free to condescend and explain how "an electronically excited species" is equivocal, as if for a naive audience. Just plain Bill (talk) 11:22, 6 June 2024 (UTC)[reply]

Ommitted word: "Luminescence is a spontaneous emission of radiation whether electronically or from a vibrationally excited species." An improvement, but not by much. I'd gladly walk that back in favor of the Encyclopedia Britannica description noted above.

I'll defer to your erudition re an explanation, as if for a naive ~~audience~~ reader, of what an electronically excited species is supposed to mean.

NOTE 1: Please avoid ultracrepidarian conflation of animals such as glow worms, fire flies, or electric eels (and rays) that are capable of electronic excitation versus an "electroncally excited species" of animals in the Linnaean taxonomy.

NOTE 2: Please explain how "Luminescence is a spontaneous emission of radiation from an electronically or vibrationally excited species" is broad enough to apply to things like a plasma screen, certain watch dials, or the aurora borealis. Are those things generally construed to be electroncally excited species? Kent Dominic·(talk) 12:21, 6 June 2024 (UTC)[reply]

"Species" is not used here in the sense of "unit of biological taxonomy".

The aurora appears when gaseous species in the upper atmosphere are excited by electrons and other charged particles. Plasma screens use ionized gaseous species, excited electronically. Similarly, the phosphors of a cathode ray tube are excited by beamed electrons. (Vacuum tubes were the first electronic devices, not merely electrical.) Phosphorescent watch dials may be excited by photons, or by the products of radioactive decay.

Bioluminescence is a chemical process, having nothing to do with electric eels.

Thanks to your spectacularly labyrinthine non-explanations, I now see that "electronically or vibrationally excited species" may not be broad enough to cover all cases of luminescence. Carry on, Just plain Bill (talk) 13:16, 6 June 2024 (UTC)[reply]

"Species" is not used here in the sense of "unit of biological taxonomy" is a perfectly reasonable premise that's all but certainly what the source intended. The problem is that the most common concept associated with species relates to biological taxonomy. The point of the article should be to provide a simple description of luminescence in a plain English way that reaches general readers' sensibilities without presuming they know what electronically or vibrationally excited species means.

I don't intend to edit the article based on the alternative wording I suggested above. Indeed, after I tweaked the lede for formatting and readability re the quotation marks, I decided the lede is too arcane for the average reader. Rather than changing the lede to accord with the Encyclopedia Britannica tack, I'm simply linking that source, rather than Wikipedia, as a reference for my readers' benefit. Kent Dominic·(talk) 14:31, 6 June 2024 (UTC)[reply]