Profile of spectral line

Shapes or profiles of spectral lines are often very important for obtaining information about the physical system under observation. Thus a spectral profile can tell us the state of a stellar atmosphere, or it can be used as diagnostic for a plasma. The line shape of an NMR spectrum may disclose the internal motion of nuclei in a molecular system. The information thus obtained is admittedly not extremely detailed, but it may be very useful particularly when combined with other information, and often it is the only data available. 

The profiles of spectral lines as are obtained in plasma sources at atmospheric pressure are illustrated by the high-resolution records of a number of rare earth spectral lines obtained in the case of an inductively coupled plasma source (ICP) (Fig. 2) [14],... 

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