Nitrogen Systems: First Positive, Second Positive, First Negative

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Discussion Overview

The discussion revolves around the terminology and concepts related to the "first positive," "second positive," and "first negative" systems of nitrogen in the context of spectroscopy. Participants seek to clarify the meaning of these terms, the transitions involved, and the states of the nitrogen molecule during these processes.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant expresses confusion about the terms "first positive," "second positive," and "first negative" systems in spectroscopy, seeking assistance to understand the underlying transitions and molecular states.
  • Another participant shares a reference to a paper that discusses the first positive and second positive systems, indicating a shared interest in finding detailed information.
  • A third participant cites G. Herzberg's work, explaining that the terms "positive" and "negative" refer to the occurrence of bands in different regions of an electric discharge, with positive groups associated with neutral molecules and negative groups with positively charged molecular ions.
  • Some participants note the original poster has not returned to the discussion since their initial post, indicating a lack of ongoing engagement.

Areas of Agreement / Disagreement

Participants generally express a lack of clarity regarding the terminology, and while some references are provided, there is no consensus on a comprehensive understanding of the concepts discussed.

Contextual Notes

The discussion highlights a reliance on specific literature for definitions and explanations, indicating potential limitations in the participants' understanding of the terms without further context or detailed sources.

Yohan24
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What is the "first positive", "second positive", "first negative" systems of nitrogen

Hello,
I have been trying to catch up on spectroscopy theory, and I'm trying to get a grasp on what all the terms mean. I constantly seem the terms "first positive system", etc... coming up, and I'm not sure I understand what that means in terms of the transitions that are taking place, what state the molecule is in and so on. I've looked all over but it seems most articles that I find take it for granted that everyone knows what these things mean. Maybe I'm over thinking, or not thinking at all. Any assistance would be greatly appreciated.
Cheers.
- Y
 
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Hi Yohan24,

I am literally searching for the same thing and I found the following paper talks a bit about the first positive and second positive(at p118)
http://www.stanford.edu/group/Zarelab/publinks/13.pdf

Hope this helps. Please let me know if you find anything in more detail. Thanks!

Cheers,
hggreen
 


In G. Herzberg, Molecular Spectra and Molecular Structure. I. Spectra of Diatomic Molecules (Van Nostrand, Princeton, 1950), footnote on page 51:
The designation negative and positive groups (or bands) refer to the occurrence of these bands in the negative glow or the positive column, respectively, of an electric discharge. The positive groups are due to the neutral molecule, the negative groups to the singly positively charged molecular ion.
 


Unfortunately, this was the OP's only post, and he/she hasn't come back since May 29, 2012.

Zz.
 


ZapperZ said:
Unfortunately, this was the OP's only post, and he/she hasn't come back since May 29, 2012.

Zz.

I saw that, but I answered anyway as the information seemed of interest to hggreen.
 


Thank you DrClaude! That helps a lot.

-hggreen

DrClaude said:
In G. Herzberg, Molecular Spectra and Molecular Structure. I. Spectra of Diatomic Molecules (Van Nostrand, Princeton, 1950), footnote on page 51:
 

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