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I'm trying to do some processing of optical emission spectra from sputtering plasmas, and am confused by what NIST means by 'easily reversed' in their notation. Anyone have a clue?

user1586
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wordsforthewise
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  • Cross-posted to physcs: http://physics.stackexchange.com/questions/191002/what-does-easily-reversed-mean-in-the-nist-spectral-database – Chris Mueller Jun 24 '15 at 10:56

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This means that the line in question can be apparent or not depending on whether the spectrum has been absorbed for other reasons. Or as Wikipedia states:

...the reabsorption near the line center may be so great as to cause a self reversal in which the intensity at the center of the line is less than in the wings.

Also, there is a paper that takes this topic more in depth: Effect of Self-Reversed Spectral Lines and the Temperature of the Switching Arc Plasma

hazzey
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  • Hmm, yeah I saw that but wasn't sure it was relevant to the NIST definition. So essentially, the peak could be split into two? What is reabsorbing the emission only at the center line? The wikipedia explanation is nebulous. – wordsforthewise Jun 24 '15 at 01:45
  • Haha, in that paper, the 'curves of blackening'. Sounds like a futuristic-medieval mashup. – wordsforthewise Jun 24 '15 at 01:48