A report on Phosphorescence

Phosphorescent bird figure
Phosphorescent, europium-doped, strontium silicate-aluminate oxide powder under visible light, fluorescing/phosphorescing under long-wave UV light, and persistently phosphorescing in total darkness
Jablonski diagram of an energy scheme used to explain the difference between fluorescence and phosphorescence. The excitation of molecule A to its singlet excited state (1A*) may, after a short time between absorption and emission (fluorescence lifetime), return immediately to ground state, giving off a photon via fluorescence (decay time). However, sustained excitation is followed by intersystem crossing to the triplet state (3A) that relaxes to the ground state by phosphorescence with much longer decay times.
After an electron absorbs a photon of high energy, it may undergo vibrational relaxations and intersystem crossing to another spin state. Again the system relaxes vibrationally in the new spin state and eventually emits light by phosphorescence.
An extremely intense pulse of short-wave UV light in a flashtube produced this blue persistent-phosphorescence in the amorphous, fused silica envelope, lasting as long as 20 minutes after the 3.5 microsecond flash.
An electron microscope reveals vacancy defects in a crystalline lattice of molybdenum disulfide. The missing sulfur atoms leave dangling bonds between the molybdenum atoms, creating a trap in the empty spaces.
Phosphorescent elements of a wrist watch that had been exposed to bright light: clock face with twelve dots as well as minute and hour hand
thumb|Zinc sulfide (left) and strontium aluminate (right), in visible light, in darkness, and after 4 minutes in the dark.
thumb|Calcium sulfide (left) and metal-earth silicate (right) phosphoresce in red and blue respectively.
Before image of capturing a shadow on a phosphorescent wall.
After image of capturing a shadow on a phosphorescent wall.

Type of photoluminescence related to fluorescence.

- Phosphorescence
Phosphorescent bird figure

16 related topics with Alpha

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Fluorescent minerals emit visible light when exposed to ultraviolet light.

Fluorescence

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Emission of light by a substance that has absorbed light or other electromagnetic radiation.

Emission of light by a substance that has absorbed light or other electromagnetic radiation.

Fluorescent minerals emit visible light when exposed to ultraviolet light.
Fluorescent marine organisms
Fluorescent clothes used in black light theater production, Prague
Lignum nephriticum cup made from the wood of the narra tree (Pterocarpus indicus), and a flask containing its fluorescent solution
Matlaline, the fluorescent substance in the wood of the tree Eysenhardtia polystachya
Jablonski diagram. After an electron absorbs a high-energy photon the system is excited electronically and vibrationally. The system relaxes vibrationally, and eventually fluoresces at a longer wavelength.
Fluorescent security strip in a US twenty dollar bill under UV light
Fluorescent coral
Fluorescence has multiple origins in the tree of life. This diagram displays the origins within actinopterygians (ray finned fish).
Fluorescent marine fish
Aequoria victoria, biofluorescent jellyfish known for GFP
Fluorescent polka-dot tree frog under UV-light
Fluorescing scorpion
Fluorescence of aragonite
Fluorescent paint and plastic lit by UV tubes. Paintings by Beo Beyond
Endothelial cells under the microscope with three separate channels marking specific cellular components

Fluorescent materials cease to glow nearly immediately when the radiation source stops, unlike phosphorescent materials, which continue to emit light for some time after.

A chemoluminescent reaction in an Erlenmeyer flask

Chemiluminescence

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Luminol and [B] is hydrogen peroxide in the presence of a suitable catalyst we have:

Luminol and [B] is hydrogen peroxide in the presence of a suitable catalyst we have:

A chemoluminescent reaction in an Erlenmeyer flask
Bioluminescence in nature: A male firefly mating with a female of the species Lampyris noctiluca.
Chemiluminescence after a reaction of hydrogen peroxide and luminol
Green and blue glow sticks

This state then decays into an electronic ground state and emits light through either an allowed transition (analogous to fluorescence) or a forbidden transition (analogous to phosphorescence), depending partly on the spin state of the electronic excited state formed.

White phosphorus exposed to air glows in the dark

Phosphorus

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Chemical element with the symbol P and atomic number 15.

Chemical element with the symbol P and atomic number 15.

White phosphorus exposed to air glows in the dark
The tetrahedral structure of P4O10 and P4S10.
A stable diphosphene, a derivative of phosphorus(I).
Robert Boyle
Guano mining in the Central Chincha Islands, ca. 1860.
Mining of phosphate rock in Nauru
Match striking surface made of a mixture of red phosphorus, glue and ground glass. The glass powder is used to increase the friction.
Phosphorus explosion

The term phosphorescence, meaning glow after illumination, derives from this property of phosphorus, although the word has since been used for a different physical process that produces a glow.

Fluorescent solutions under UV light. Absorbed photons are rapidly re-emitted under longer electromagnetic wavelengths.

Photoluminescence

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Light emission from any form of matter after the absorption of photons (electromagnetic radiation).

Light emission from any form of matter after the absorption of photons (electromagnetic radiation).

Fluorescent solutions under UV light. Absorbed photons are rapidly re-emitted under longer electromagnetic wavelengths.
Schematic for the excitation-relaxation processes of photoluminescence

Time periods between absorption and emission may vary: ranging from short femtosecond-regime for emission involving free-carrier plasma in inorganic semiconductors up to milliseconds for phosphoresence processes in molecular systems; and under special circumstances delay of emission may even span to minutes or hours.

Persistent luminescence

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Commonly referred as phosphorescence, persistent luminescence is the emission of light by a phosphorescent material after an excitation by ultraviolet or visible light.

Forbidden mechanism

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Spectral line associated with absorption or emission of photons by atomic nuclei, atoms, or molecules which undergo a transition that is not allowed by a particular selection rule but is allowed if the approximation associated with that rule is not made.

Spectral line associated with absorption or emission of photons by atomic nuclei, atoms, or molecules which undergo a transition that is not allowed by a particular selection rule but is allowed if the approximation associated with that rule is not made.

An example is phosphorescent glow-in-the-dark materials, which absorb light and form an excited state whose decay involves a spin flip, and is therefore forbidden by electric dipole transitions.

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Radioactive decay

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Process by which an unstable atomic nucleus loses energy by radiation.

Process by which an unstable atomic nucleus loses energy by radiation.

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Pierre and Marie Curie in their Paris laboratory, before 1907
Taking an X-ray image with early Crookes tube apparatus in 1896. The Crookes tube is visible in the centre. The standing man is viewing his hand with a fluoroscope screen; this was a common way of setting up the tube. No precautions against radiation exposure are being taken; its hazards were not known at the time.
Graphic showing relationships between radioactivity and detected ionizing radiation
Alpha particles may be completely stopped by a sheet of paper, beta particles by aluminium shielding. Gamma rays can only be reduced by much more substantial mass, such as a very thick layer of lead.
137Cs decay scheme showing half-lives, daughter nuclides, and types and proportion of radiation emitted
Transition diagram for decay modes of a radionuclide, with neutron number N and atomic number Z (shown are α, β±, p+, and n0 emissions, EC denotes electron capture).
Types of radioactive decay related to neutron and proton numbers
Simulation of many identical atoms undergoing radioactive decay, starting with either 4 atoms (left) or 400 (right). The number at the top indicates how many half-lives have elapsed.
Example of diurnal and seasonal variations in gamma ray detector response.
Gamma-ray energy spectrum of uranium ore (inset). Gamma-rays are emitted by decaying nuclides, and the gamma-ray energy can be used to characterize the decay (which nuclide is decaying to which). Here, using the gamma-ray spectrum, several nuclides that are typical of the decay chain of 238U have been identified: 226Ra, 214Pb, 214Bi.
The trefoil symbol used to warn of presence of radioactive material or ionising radiation
2007 ISO radioactivity hazard symbol intended for IAEA Category 1, 2 and 3 sources defined as dangerous sources capable of death or serious injury<ref>IAEA news release Feb 2007</ref>
The dangerous goods transport classification sign for radioactive materials

Radioactivity was discovered in 1896 by scientists Henri Becquerel and Marie Curie, while working with phosphorescent materials.

Excited electrons can undergo intersystem crossing to a degenerate state with a different spin multiplicity.

Intersystem crossing

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Isoenergetic radiationless process involving a transition between the two electronic states with different spin multiplicity.

Isoenergetic radiationless process involving a transition between the two electronic states with different spin multiplicity.

Excited electrons can undergo intersystem crossing to a degenerate state with a different spin multiplicity.
Singlet and triplet energy levels.

The radiative decay from an excited triplet state back to a singlet state is known as phosphorescence.

Cathode-ray tube using electromagnetic focus and deflection. Parts shown are not to scale.

Cathode-ray tube

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[[File:CRT monochrome.png|thumb|250px|Cutaway rendering of a monochrome CRT:1. Deflection coils2. Electron beam3. Focusing coil4. Phosphor layer on the inner side of the screen; emits light when struck by the electron beam5. Filament for heating the cathode6. Graphite layer on the inner side of the tube7. Rubber or silicone gasket where the anode voltage wire enters the tube (anode cup)8. Cathode9. Air-tight glass body of the tube10. Screen11. Coils in yoke12. Control electrode regulating the intensity of the electron beam and thereby the light emitted from the phosphor13. Contact pins for cathode, filament and control electrode14. Wire for anode high voltage.

[[File:CRT monochrome.png|thumb|250px|Cutaway rendering of a monochrome CRT:1. Deflection coils2. Electron beam3. Focusing coil4. Phosphor layer on the inner side of the screen; emits light when struck by the electron beam5. Filament for heating the cathode6. Graphite layer on the inner side of the tube7. Rubber or silicone gasket where the anode voltage wire enters the tube (anode cup)8. Cathode9. Air-tight glass body of the tube10. Screen11. Coils in yoke12. Control electrode regulating the intensity of the electron beam and thereby the light emitted from the phosphor13. Contact pins for cathode, filament and control electrode14. Wire for anode high voltage.

Cathode-ray tube using electromagnetic focus and deflection. Parts shown are not to scale.
A cathode-ray tube as found in an oscilloscope
Cutaway rendering of a color CRT:
1. Three electron emitters (for red, green, and blue phosphor dots)
2. Electron beams
3. Focusing coils
4. Deflection coils
5. Connection for final anodes (referred to as the "ultor" in some receiving tube manuals)
6. Mask for separating beams for red, green, and blue part of the displayed image
7. Phosphor layer (screen)with red, green, and blue zones
8. Close-up of the phosphor-coated inner side of the screen
The rear of a 14-inch color cathode-ray tube showing its deflection coils and electron guns
Typical 1950s United States monochrome television set
Snapshot of a CRT television showing the line of light being drawn from left to right in a raster pattern
Animation of the image construction with interlacing method
Color computer monitor electron gun
Braun's original cold-cathode CRT, 1897
Small circular CRTs during manufacture in 1947 (screens being coated with phosphor)
A portable monochrome CRT TV
A Trinitron CRT computer monitor
A monochrome CRT as seen inside a TV. The CRT is the single largest component in a CRT TV.
A monochrome CRT as seen inside a Macintosh Plus computer
An aluminized monochrome CRT. The black matte coating is aquadag.
The deflection yoke over the neck of a monochrome CRT. It has two pairs of deflection coils.
Magnified view of a delta-gun shadow mask color CRT
On the left: Magnified view of In-line phosphor triads (a slot mask) CRT. On the right: Magnified view of Delta-gun phosphor triads.
Magnified view of a Trinitron (aperture grille) color CRT. A thin horizontal support wire is visible.
CRT triad and mask types
Spectra of constituent blue, green and red phosphors in a common CRT
The in-line electron guns of a color CRT TV
A degaussing in progress
Mu metal magnetic shields for oscilloscope CRTs
The front of a Sony Watchman monochrome CRT
A flat monochrome CRT assembly inside a 1984 Sinclair TV80 portable TV
An oscilloscope showing a Lissajous curve
The electron gun of an oscilloscope. A pair of deflection plates is visible on the left.
The Tektronix Type 564: first mass-produced analog phosphor storage oscilloscope
Nimo tube BA0000-P31
A comparison between 21-inch Superslim and Ultraslim CRT
A CRT during an implosion
Datapoint 1500 terminal with exposed chassis, with its CRT suffering from a "cataract" due to aging PVA
A monochrome CRT with 110° deflection
A monochrome CRT with 90° deflection
Older monochrome CRT<ref>http://www.earlytelevision.org/postwar_crts.html https://www.crtsite.com/tv-crt.html http://www.earlytelevision.org/14ap4_construction.html</ref> without aluminum, only aquadag
The electron gun of a monochrome CRT
The side of a Sony Watchman monochrome CRT. One of the pairs of deflection coils is easily noticeable.

A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen.

Sphalerite, the more common polymorph of zinc sulfide

Zinc sulfide

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Inorganic compound with the chemical formula of ZnS.

Inorganic compound with the chemical formula of ZnS.

Sphalerite, the more common polymorph of zinc sulfide
Wurtzite, the less common polymorph of zinc sulfide
Mixtures of zinc and sulfur react pyrotechnically, leaving behind zinc sulfide.

Zinc sulfide, with addition of few ppm of suitable activator, exhibits strong phosphorescence (described by Nikola Tesla in 1893 ), and is currently used in many applications, from cathode ray tubes through X-ray screens to glow in the dark products.