Emission line
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An emission line is a narrow feature in a spectrum produced when atoms, ions, molecules, or other systems release radiation at particular wavelengths. It commonly occurs when an excited state loses energy and transitions to a lower state.
The emitted photon has an energy equal to the difference between the two states. Because allowed energy levels are characteristic of each species, emission lines can be used as identifying fingerprints.
The line's intensity, width, shape, position, and splitting can reveal abundance, temperature, density, pressure, motion, magnetic fields, and interactions with surrounding matter.
Emission lines are observed in laboratory discharges, flames, lasers, planetary atmospheres, nebulae, stars, galaxies, and many other radiating systems.
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- Source / publisher: Wikipedia
- URL type: WWW
- Credits: Wikipedia
- URL: https://en.wikipedia.org/wiki/Emission_line