Talk:Phosphorescence/Archives/2013

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Yikes, this is a perfect page to explain the background of phosphorescence to a Physics PhD, but it happens that most people aren't.... can someone please explain what it is? Rob Hooft 16:26, 25 Apr 2004 (UTC)

Can phosphorescence be considered a thermal phenomenon? lysdexia 10:26, 19 Oct 2004 (UTC)

In a nutshell phosphorescence results in the delayed emission of light from a lumophore after photo-excitation. I tried to clean up the definition a little and separate out the blood and guts, but phosphorescence really is defined by the spin multiplicity of the excited species.

I do not think you can categorize phosphorescence as a strictly thermal phenomenon, though vibrational relaxation does dissipate energy as heat.

Fearofcarpet 21:34, 17 Mar 2005 (UTC)

Explanation needed please

Could someone please either explain in layman's terms or omit

• quantum mechanically forbidden
• state singlet and state triplet
• spin multiplicity
• kinetically slow

Thanks! This introductory paragraph is very off-putting to non-experts as it stands. Lupin|talk|popups 01:37, 15 September 2005 (UTC)

Error in the equation

The equation says that the triplet level returns to a singlet and then decays emiting a photon. In fact, the transition is usually directly from the triplet level to the ground singlet, usually the phoshorescent photon has lower energie than the fluorescent. (Klessinger, Martin and Michl, Josef, Excited states and photochemistry of organic molecules, pg 266, 1995) —Preceding unsigned comment added by 85.177.46.12 (talk) 21:16, 9 August 2008 (UTC)

When the outgoing photon has lower frequency than the incoming, as in phosphorescence and fluorescence, where does the energy difference go? to heat? —Preceding unsigned comment added by Kinzele (talk • contribs) 19:53, 29 May 2010 (UTC)

Yes, to heat. Materialscientist (talk) 00:16, 30 May 2010 (UTC)

Don't lose technical details

When addressing Lupin's suggestions, please do not lose the technical details that currently exist. Phosphorescence is a very specific type of luminescence, and as such should not simply restate that definition. It may be necessary to add a simplified introduction, or perhaps add some diagrams to indicate what is meant by singlet/triplet and dipole allowed/disallowed transitions. But as this is the heart of the physics, I strongly urge that it not be simply omitted.

crick22 19:00, 17 September 2005

Hmmm...

Yeah. I'm going to throw in the idea that perhaps this shouldn't be as much of a scientific article (though that can certainly be retained) as much as say... "It makes things freakin' glow. Cool." I mean, let's be honest. An encyclopaedia is supposed to be general. This isn't.

Are we just an encyclopedia, or better than an encyclopedia? I come here to learn stuff, I now have a bunch more pointers to things I otherwise would never have known existed. What in the hell is a triplet state? I dunno, but I can now find out - because someone said it was important. So I disagree with the loss of technical details. Yes, I would like some more laymen's stuff on this. But somethings *are* complex.

~ender 2006-05-24 09:33:MST

This article is not "better" than an encyclopedic article by many measures that I can think of. There are many reasons one would want to come to an article on this subject -- the current treatment should be restricted to a "how it works" section, with the larger article being about, say, the position of phosphorescence in culture and history, its replacement of radium paint, lists of materials, and its practical and decorative uses. I mean, for crying out loud, "Glow in the dark" redirects here. This article is like an ambush. It reminded me of the essay generator at (http://www.elsewhere.org/pomo). It's readable if you try, but even if you do so you will have learned nothing. --Kalthare 09:53, 18 June 2006 (UTC)

Laymen's explanation added

I have added a paragraph attempting to provide a simpler explanation. However, the technical details given in the original version are excellent, and are truly helpful in defining the phenomenom clearly and unambiguously. - Xgu 22:38, 5 December 2005 (UTC)

List of materials?

The article mentions that there are numbers of different materials which have various slow time states, from larger than 10 nanoseconds, upwards to hours... I'd like to know what materials disperse stuff longest, and also, what types of output - is it completely linear degradation? Etc.
~ender 2006-05-24 9:36:MST

The degradation is normally roughly exponential. Occasionally multiple exponential decays can be observed depending on the rate determining step of the phosphoresent mechanism. 08/02/07

I'll second the idea for a list of materials. I came to this page because my 8 year old kid has some stuff in his bedrooom that glows when the lights are turned off. From sprinkling salt on the kitchen gas rings he knows sodium can create a yellow light and we see the same colour in sodium streetlights. I wanted to tell him that something else had a different colour and there is nothing on the phosphorescence page really helps.

Surely an idea of what phosphoresces is essential, even if the list is far from complete. Luckily the Wikipedia page for cats doesn't jump in at the deep end explaining their DNA!

Yes, please add a list of "glow in the dark materials"! Do they all contain Phosphor? Apus 12:00, 28 November 2006 (UTC)

A list of 'glow in the dark materials' is not relevant to this page because most glow in the dark materials do not glow because they are phosphorescent. Chemi-luminescence is a more common mechanism. Phosphor is a substance found inside television screens that can produce light when it is hit by a stream of electrons. It is not phosphorescent. An example of a phosphorescent material with particular relevance to current chemical research (possible future application in OLEDs) is iridium triphenylphosphine [Ir(ppy)₃], and derivatives. These would 'glow in the dark', but the glow wouldn't be observable to the human eye because they have phosphorescent lifetimes in the order of microseconds (10^-6 s) 08/02/07

"List of glow-in-the-dark materials" probably refers to what compounds are commercially used for phosphorescent "glow-in-the-dark" objects. According to This page, zinc sulfide and Strontium Aluminate as two compounds that are used for their phosphorescent properties. Tritium and promethium are used as radiation sources for non-charging phosphorescent items such as watches.

From Photoluminescence:

Two common pigments are used in photoluminescent materials, zinc sulfide and strontium oxide aluminate. Use of zinc sulfide for
 safety related products dates back to the 1930s. However, the development of strontium oxide aluminate, with a luminance 
approximately 10 times greater than zinc sulfide, has relegated most zinc sulfide based products to the novelty category. Strontium 
oxide aluminate based pigments are now used in exit signs, pathway marking, and other safety related signage. 

Talyian 11:34, 4 April 2007 (UTC)

The problem is that "Glow in the dark" covers many more things than mere Phosphorescence. I know that's not what *I* was looking for when I came here. I was looking for children's glow in the dark toys. It is a stupid redirect and I would fix it but I am sleepy. Saudade7 02:46, 20 November 2007 (UTC)

Diagram?

It would be nice if someone could make a diagram showing the energy levels and transitions. -Scott, 9/19/06

comment: Add the jablonski diagram!

Disambiguation

Phosphorescence is comonly used to refer to the emission of light by bioluminescent plankton. This is not phosphorescence in the tecnical sense and is rightly not described in this article. I put in a disambiguation statement at the top of this page.

Are there other things which are commonly called phosphorescence which fall outside this article?

I suggest a separate article for "glow in the dark" which links briefly describes phosphorescence, chemoluminescence, bioluminescence, uv flourescence in the context of specific examples and has links to the technical articles.Threetwoone 01:17, 27 September 2006 (UTC)

Explanation needed please: Spin orbit coupling

Can anyone explain why the presence of spin orbit coupling causes relaxation of the spin selection rules that render the event of phosphorescence unlikely? Thanks.

Removed dumb stuff, edited some other stuff and on the same note added what I thought was a bit more descriptive and accessible foreword to that chunk of hardcore quantum pyrotechnics. 124.243.128.11 04:57, 7 November 2006 (UTC)

CRTs

The article needs to specifically state whether or not CRT screen chemicals use this. And if so, please name the specific chemical compounds, and give the specific times.-69.87.193.242 12:57, 4 April 2007 (UTC)

WikiProject class rating

This article was automatically assessed because at least one WikiProject had rated the article as stub, and the rating on other projects was brought up to Stub class. BetacommandBot 10:01, 10 November 2007 (UTC)

Temperature-dependence of phosphorescence and phosphorescent garden decorations

I stumbled upon this page in the process of trying to figure out why I would need to bring in my phosphorescent garden decorations in freezing temperatures, as instructed in the package insert provided with the items. This extremely “lay” application may not have occurred to the original writer(s) of this page but, as these types of items are becoming increasingly popular, this may not be the last time you hear about it. Anyway, I was able to find on another site that phosphorescence is temperature dependent but there wasn’t much of an explanation beyond that. I don’t know if keeping the items from freezing is to prevent damage to the items or just because the phosphorescent process is inefficient in freezing temperatures. (Also, I will add that your explanation of the physics involved in phosphorescence is quite interesting but I wasn’t really in the frame of mind this time around to concentrate hard enough to really digest it. I’m a biologist so not unversed in scientific process but I never got comfortable with physics.)--Jspicker 19:23, 2 December 2007 (UTC)

Health risks?

A section on health risks, if any, is needed, I think. Imagine Reason (talk) 14:34, 18 April 2008 (UTC)

I don't believe there are any significant health risks related to this subject. The light that is emitted is just like ordinary light. If the phosphorescent light is green, it is just like most other green light you can see.Shandolad (talk) —Preceding undated comment was added at 12:53, 27 September 2008 (UTC).

A health risk can be in concrete phosphorescent material, that can include any harmful chemicals (heavy metals like cadmium or even radioactive materials).Krasss (talk) —Preceding undated comment was added at 09:20, 25 November 2008 (UTC).

hi:)

Glowing in combustion

The redirection of "glowing" to this page is misleading in terms of the glowing resulting from combustion. For example, smouldering combustion of a solid fuel. I suggest creating a new entry for glowing that differentiates between light emission at moderate temperatures and phosphorescence. Opinions? Grein (talk) 21:21, 24 October 2009 (UTC)

• a redirect to radiation ? V8rik (talk) 21:46, 24 October 2009 (UTC)

The glow caused by combustion is usually termed blackbody radiation. That would probably be a more direct link. Of course, that applies to smoldering. With flame, (plasma), I believe it's more a combination of spectral radiation and blackbody radiation, which is often called greybody radiation. Zaereth (talk) 17:03, 29 October 2009 (UTC)

Uninformative photo

The picture of a green bird with no explanation is useless. Has it's DNA been altered so it glows? Has it been painted? Is it a toy? Your guess is no better than mine.
--68.127.87.182 (talk) 04:07, 21 July 2011 (UTC)Doug Bashford

It looks like a bird statue made out of (or covered with) phosphorescent material. --Spmoura (talk) 06:24, 14 June 2012 (UTC)

Energy scheme

Is the energy scheme correctly represented here? Excitation from S=0 to S=0? Isn't that notation wrong? Wouldn't it be S0 to S1 (fluorescence) and then S1 to T1 to S0 (phosphorecence) just like the following equation is showing? --Spmoura (talk) 06:22, 14 June 2012 (UTC)

Excitation is usually optical, and it should be efficient, i.e. involve a dipole-allowed transition. Thus an S=0 <-> S=0 transition is appropriate for excitation and fluorescence, since photon doesn't carry spin and thus can't change electron spin. Materialscientist (talk) 06:37, 14 June 2012 (UTC)

Ops, erase that. You're right, I got confused by the S=0 (singlet) S=1 (triplet) notations as opposed to the S₀ and S₁ (singlet ground and excited states) and T₁ (triplet state). Maybe the scheme could be changed to include the words 'singlet' and 'triplet' to mach the equation's notations. S₀ (singlet, spin = 0) to S₁ (singlet, spin = 0) and T₁ (triplet, spin = 1). --Spmoura (talk) 23:16, 19 July 2012 (UTC)