emission spectrum

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emission spectrum

physics

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June 26, 2026

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An emission spectrum is produced when an atom, ion, or molecule transitions from a higher energy state to a lower one, releasing energy in the form of electromagnetic radiation. This emitted radiation, when separated by wavelength, creates a spectrum of bright lines or bands against a dark background. These characteristic patterns, often called a "fingerprint," can be used to identify the specific element or molecule present. The energy levels within atoms and molecules are quantized, meaning they can only exist at discrete energy values. When a transition occurs between these levels, the energy difference dictates the frequency of the emitted radiation, following the equation (\Delta E = h\nu). This phenomenon is fundamental to spectroscopy, a field used for chemical analysis and understanding atomic and molecular structures.123456

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chemical element
Stars and gas clouds
…a pattern is called an emission, or bright-line, spectrum. When light passes through a gas or cloud at a lower temperature than the light source, the gas absorbs at its identifying wavelengths, and a dark-line, or absorption, spectrum will be formed.
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…a pattern is called an emission, or bright-line, spectrum. When light passes through a gas or cloud at a lower temperature than the light source, the gas absorbs at its identifying wavelengths, and a dark-line, or absorption, spectrum will be formed.
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radiation measurement
Inorganic scintillators
The emission spectrum of NaI(Tl) is peaked at a wavelength corresponding to the blue region of the electromagnetic spectrum and is well matched to the spectral response of photomultiplier tubes. Thallium-activated cesium iodide [CsI(Tl)] also produces excellent light yield but has two relatively long decay components…
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The emission spectrum of NaI(Tl) is peaked at a wavelength corresponding to the blue region of the electromagnetic spectrum and is well matched to the spectral response of photomultiplier tubes. Thallium-activated cesium iodide [CsI(Tl)] also produces excellent light yield but has two relatively long decay components…
Read More

spectrum
An emission spectrum consists of all the radiations emitted by atoms or molecules, whereas in an absorption spectrum portions of a continuous spectrum (light containing all wavelengths) are missing because they have been absorbed by the medium through which the light has passed; the missing wavelengths…
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An emission spectrum consists of all the radiations emitted by atoms or molecules, whereas in an absorption spectrum portions of a continuous spectrum (light containing all wavelengths) are missing because they have been absorbed by the medium through which the light has passed; the missing wavelengths…
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spectroscopy
General methods of spectroscopy
…either in the form of emission spectra, which show one or more bright lines or bands on a dark background, or absorption spectra, which have a continuously bright background except for one or more dark lines.
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…either in the form of emission spectra, which show one or more bright lines or bands on a dark background, or absorption spectra, which have a continuously bright background except for one or more dark lines.
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Stark effect
Stark observed the hydrogen spectrum emitted just behind the perforated cathode in a positive-ray tube. With a second charged electrode parallel and close to this cathode, he was able to produce a strong electric field in a space of a few millimetres. At electric field intensities of 100,000 volts…
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Stark observed the hydrogen spectrum emitted just behind the perforated cathode in a positive-ray tube. With a second charged electrode parallel and close to this cathode, he was able to produce a strong electric field in a space of a few millimetres. At electric field intensities of 100,000 volts…
Read More