fluorescence


fluo·res·cence

noun \-ˈre-sən(t)s\

Definition of FLUORESCENCE

:  luminescence that is caused by the absorption of radiation at one wavelength followed by nearly immediate reradiation usually at a different wavelength and that ceases almost at once when the incident radiation stops; also :  the radiation emitted — compare phosphorescence

Examples of FLUORESCENCE

  1. <studied the fluorescence of certain elements>

Origin of FLUORESCENCE

fluorspar + opalescence
First Known Use: 1852

flu·o·res·cence

noun \-ˈes-ən(t)s\   (Medical Dictionary)

Medical Definition of FLUORESCENCE

: luminescence that is caused by the absorption of radiation at one wavelength followed by nearly immediate reradiation usually at a different wavelength and that ceases almost immediately when the incident radiation stops; also : the radiation emitted
flu·o·res·cent \-ˈes-ənt\ adjective

fluorescence

noun    (Concise Encyclopedia)

Emission of electromagnetic radiation, usually visible light, caused by excitation of atoms in a material, which then reemit almost immediately (within about 108 seconds). The initial excitation is usually caused by absorption of energy from incident radiation or particles, such as X-rays or electrons. Because reemission occurs so quickly, the fluorescence ceases as soon as the exciting source is removed, unlike phosphorescence, which persists as an afterglow. A fluorescent lightbulb is coated on the inside with a powder and contains a gas; electricity causes the gas to emit ultraviolet radiation, which then stimulates the tube coating to emit light. The pixels of a television or computer screen fluoresce when electrons from an electron gun strike them. Fluorescence is often used to analyze molecules, and the addition of a fluorescing agent with emissions in the blue region of the spectrum to detergents causes fabrics to appear whiter in sunlight. X-ray fluorescence is used to analyze minerals.

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