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Phosphorescence is a type of photoluminescence related to fluorescence. When exposed to light (radiation) of a shorter wavelength, a phosphorescent substance will glow, absorbing the light and reemitting it at a longer wavelength. Unlike fluorescence, a phosphorescent material does not immediately reemit the radiation it absorbs.
Fluorescent materials are used in applications in which the phosphor is excited continuously: cathode-ray tubes (CRT) and plasma video display screens, fluoroscope screens, fluorescent lights, scintillation sensors, white LEDs, and luminous paints for black light art. Phosphorescent materials are used where a persistent light is needed, such as ...
Light-dependent reactions of photosynthesis at the thylakoid membrane. Light-dependent reactions are certain photochemical reactions involved in photosynthesis, the main process by which plants acquire energy. There are two light dependent reactions: the first occurs at photosystem II (PSII) and the second occurs at photosystem I (PSI).
The dragonfish species which produce the red light also produce blue light in photophore on the dorsal area. [74] The main function of this is to alert the fish to the presence of its prey. [ 75 ] The additional pigment is thought to be assimilated from chlorophyll derivatives found in the copepods which form part of its diet.
Photoexcitation is the first step in a photochemical process where the reactant is elevated to a state of higher energy, an excited state.The first law of photochemistry, known as the Grotthuss–Draper law (for chemists Theodor Grotthuss and John W. Draper), states that light must be absorbed by a chemical substance in order for a photochemical reaction to take place.
In phosphorescence, even if the emission lives several seconds, this is due to deexcitation between two electronic states of different spin multiplicity. Persistent luminescence involves energy traps (such as electron or hole traps) in a material, [ 4 ] which are filled during the excitation.
“Indoles are natural compounds found in plants, animals, and the human body, often derived from the amino acid tryptophan,” Le detailed. “They are also produced by tryptophan-metabolizing ...
Photostimulated luminescence (PSL) is the release of stored energy within a phosphor by stimulation with visible light, to produce a luminescent signal. X-rays may induce such an energy storage. A plate based on this mechanism is called a photostimulable phosphor (PSP) plate (or imaging plate ) and is one type of X-ray detector used in ...