Spectral Line

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spectral line

[′spek·trəl ‚līn]
A discrete value of a quantity, such as frequency, wavelength, energy, or mass, whose spectrum is being investigated; one may observe a finite spread of values resulting from such factors as level width, Doppler broadening, and instrument imperfections. Also known as spectrum line.

Spectral Line


a thin line in an optical spectrum. Each such line can be characterized by a certain wavelength λ or frequency v = c/λ, where c is the speed of light. Spectral lines are observed in emission spectra as bright (colored) lines on a dark background and in absorption spectra as dark lines on a bright background. Each spectral line corresponds to a definite quantum transition in an atom, molecule, or crystal. Spectral lines are not strictly monochromatic: each one has a certain width Δλ.

References in periodicals archive ?
Previous studies had found a few examples of quasars whose broad absorption lines seemed to have disappeared between one observation and the next.
27 PHYSICAL REVIEW LETTERS, they present data suggesting that the spacings between absorption lines for several types of atoms 8 to 12 billion years ago were different than they are today.
Evolution of galaxies and the intergalactic matter can be studied by looking at quasar absorption lines.
This data can be displayed through absorption lines and by the relative strength shown, the D/H line can be evaluated.
In the course of observing quasars, astronomers have discovered clouds of hydrogen gas that make their presence known by absorbing some of the quasar's radiation, creating a thicket of absorption lines.
This capability allows design engineers to precisely pump narrow absorption lines in solid-state and fiber lasers with little or no active temperature control.