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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.
Example of phosphorescence Monochrome monitor Aperture grille CRT phosphors. A phosphor is a substance that exhibits the phenomenon of luminescence; it emits light when exposed to some type of radiant energy.
Electrons change energy states by either resonantly gaining energy from absorption of a photon or losing energy by emitting photons. In chemistry-related disciplines, one often distinguishes between fluorescence and phosphorescence. The former is typically a fast process, yet some amount of the original energy is dissipated so that re-emitted ...
Principally, the electron can undergo a forbidden de-excitation from the excited triplet state, the electron can undergo a forbidden de-excitation to the ground state as radiative transition, called phosphorescence, or as non-radiative process. However, this occurs on a much slower time scale, being on the order of microseconds to seconds.
Phosphorescence, traditionally defined as persistent emission of light after the end of excitation. As the definition does not fully describe the phenomenon, quantum mechanics is employed where it is defined as there is a change in spin multiplicity from the state of excitation to the emission of light.
Radioluminescent paint is a self-luminous paint that consists of a small amount of a radioactive isotope (radionuclide) mixed with a radioluminescent phosphor chemical. The radioisotope continually decays, emitting radiation particles which strike molecules of the phosphor, exciting them to emit visible light.
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.
The radiative decay from an excited triplet state back to a singlet state is known as phosphorescence. Since a transition in spin multiplicity occurs, phosphorescence is a manifestation of intersystem crossing. The time scale of intersystem crossing is on the order of 10 −8 to 10 −3 s, one of the slowest forms of relaxation. [3]