What is the difference between fluorescence and phosphorescence?

Answer

In fluorescence, an object absorbs and releases lower energy light almost simultaneously, but in phosphorescence, the release of light is delayed. Both fluorescence and phosphorescence are types of photoluminescence.

The difference in the time before light is emitted in fluorescence and phosphorescence can be explained by looking at the electronic processes involved. What happens in fluorescence is that when an orbital electron of an atom goes back to its ground state after being excited to a higher quantum state, it emits a photon of light. This occurs in a matter of milliseconds. In phosphorescence, the excitation to a higher state involves a change in the electron spin state. Because of this, the electrons cannot easily relax back to the ground state. This process can take minutes or hours.

A classic example of phosphorescent materials are objects that glow in the dark. When placed in a bright room, these items charge up for a while and then glow when moved to a dark location, and then the glowing objects would cease emitting light after some time. An example of fluorescence can be seen when using a black light. Certain objects glow immediately, but only when the black light is shining on them.

Q&A Related to "What is the difference between fluorescence..."
In both, the object absorbs photons at one frequency and re-emit them, usually at a different frequency. When the energy is absorbed, fluorescent dyes go to an unstable state, so
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Fluorescence. is light energy produced by a process where high-energy radiation (such as ultraviolet or X-ray) is absorbed by electrons surrounding an atom and is re-emitted as light
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fluorescence is when something shines due to a light being shined upon it. When the light is removed the substance no longer shines. With phosphorescence the substance continues to
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Fluorescence is the (almost) immediate emission of light by a substance that has absorbed light or radiation. Unlike fluorescence, a phosphorescent material does not immediately re-emit
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Ask.com Answer for: difference between fluorescence and phosphorescence
The Difference Between Fluorescence & Phosphorescence
Fluorescence and phosphorescence are similar, but they have their differences.... More »
Difficulty: Easy
Source: www.ehow.com
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