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 Post subject: Notation help
PostPosted: 21. July 2018, 11:59:00 AM 
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Dauernutzer

Joined: 10. July 2016, 13:53:59 PM
Posts: 101
H ave been trying to understand spectroscopic notation and have made some progress. However, when looking at the Spectral atlas of Arcturus I have come across notation I can't track down.

Examples are Q124*** , P240** and R132

I would be please to have any explanation or pointers to where to look these up as Google did not seem to help.

Thanks Andrew

PS I have spotted they are related to molecular lines but if anyone has a good reference that would be helpful.


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 Post subject: Re: Notation help
PostPosted: 21. July 2018, 14:33:46 PM 
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Meister
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Joined: 11. November 2007, 18:11:30 PM
Posts: 1334
Hi Andrew,
may be
C. R. Khitchin, Optical Astronomical Spectroscopy
will help. There is a section and list of other publications about molecular spectra. Google may help you under the keyword IR spectroscopy.

Cheers
Christian


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 Post subject: Re: Notation help
PostPosted: 22. July 2018, 09:47:07 AM 
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Meister
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Joined: 04. August 2006, 18:46:02 PM
Posts: 296
Hi Andrew,
I think it's about molecular spectroscopy. The designations are typical for the P, Q and R- branches of a vibrational band. Take a look at Wikipedia under "Rotational-vibration Spectroscopy":

"...In the simplest cases the part of the infrared spectrum involving vibrational transitions with the same rotational quantum number (ΔJ = 0) in ground and excited states is called the Q-branch. On the high frequency side of the Q-branch the energy of rotational transitions is added to the energy of the vibrational transition. This is known as the R-branch of the spectrum for ΔJ = +1. The P-branch for ΔJ = −1 lies on the low wavenumber side of the Q branch. The appearance of the R-branch is very similar to the appearance of the pure rotation spectrum, and the P-branch appears as a nearly mirror image of the R-branch"

The number behind the letter P,Q,R indicates the associated rotational transition.

Kind regards
Klaus


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 Post subject: Re: Notation help
PostPosted: 22. July 2018, 17:16:39 PM 
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Dauernutzer

Joined: 10. July 2016, 13:53:59 PM
Posts: 101
Thanks both for your replies. I understand now and know where to look if I need more detail.

Regards Andrew


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