Questions tagged [phosphorescence]

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4 votes
3 answers
158 views

Excited states and emission lifetimes

I have some doubts about the nomenclature of the lifetimes. Are singlet and fluorescence lifetimes the same? As well as the triplet and phosphorescence lifetimes? Also, can the triplet/phosphorescence ...
2 votes
1 answer
90 views

How does this coin-and-strike-paper trick work (and is it safe)?

When I was a kid I remember a thing an adult showed me where you would take a piece of strike paper from a matchbox, rest it on a "copper" coin (I have no idea what these coins are made of), ...
  • 137
0 votes
4 answers
102 views

Fluorescence: what mechanism regulates the rate of discharge of energy?

The other day, I noticed a strip of fluorescent tape when the lights in the room were turned off. The energy was discharged as a continued, faint glow, rather than one burst or flash of light. How so? ...
  • 111
0 votes
0 answers
80 views

Why does zinc sulfide have to be doped with silver to phosphoresce?

$\ce{ZnS}$ is a boring white powder and it doesnt glow in the dark, but if its doped with silver it starts to show some phosphorescent properties.How does silver force zinc sulfide to do that?
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2 votes
0 answers
515 views

Data analysis in TCSPC for fluorescene decay (reconvolution with measured IRF)

I am trying to understand the data analysis of fluorescence decay counts measured by TCSPC technique, particularly with reconvolution with measured IRF. I am able to get the fitted counts (given by ...
  • 139
1 vote
0 answers
80 views

Common chemcials that produce phosphorescence

Are there any common lab chemicals or household stuff that produce phosphorescence? I am aware of ZnS, CaS, Fluorescein, Erythrosin B, Vanillin Benzaldehyde, Vitamin B2, Tryptophan etc. I just need ...
  • 139
0 votes
0 answers
38 views

When an electron is excited to a singlet state, must it flip its spin state to enter the triplet state and flip once more to the ground state?

I understand the Jablonski diagram in that it has intersystem crossing from the singlet state to the triplet state, but how many spin switches are necessary to complete to phosphores? When an electron ...
  • 21
0 votes
1 answer
2k views

Why does zinc sulfide glow when hit by electrons? [duplicate]

In cathode ray tube experiment in order to check the direction of flow of electrons a hole was made in a note and behind it phosphorescent material zinc sulfide it was coated. Why does zinc sulfide ...
  • 581
4 votes
1 answer
764 views

Why are glow-in-the-dark things usually green?

I've noticed that many glow-in-the-dark objects you can purchase in the store are green. Occasionally I would come across something that was orange or blue, but mostly it seems that green is the ...
6 votes
2 answers
479 views

Why do glow-in-the-dark substances dim gradually?

Related: How do things glow in the dark? Growing up, I had glow-in-the-dark stars on my ceiling and after being "charged" by having my lights on, they would phosphoresce for quite some time. ...
3 votes
1 answer
966 views

Why is a spin change favourable in intersystem crossing?

All phosphorescent molecules go through the following transitions: $$\text{excited singlet state}$$ $$\Bigg\downarrow$$ $$\text{[intersystem crossing]}$$ $$\Bigg\downarrow$$ $$\text{ excited triplet ...
  • 133
8 votes
1 answer
108 views

Is it right to say that fluorescent lamps are actually fluorescent?

Fluorescence occurs rapidly ($\approx 10^{-6}$ to $10^{-9}$ s) but phosphorescence is slow, and is therefore observable ($> 10^{-4}$ s). So, is it right to say that fluorescent lamps actually ...
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