B General question about series limits and strong lines of the emissions spectrum

[James Kahn]

TL;DR

General question about series limits and strong lines of the emissions spectrum.

I have been learning about the emissions spectrum for the periodic table of elements and I noticed for example that the NIST database for the strong lines does not include the series limits for hydrogen. For example the NIST does not include 364.6 nm for the Balmer series limit and 820.4 nm for the Paschen series limit found in the wikipedia article etc.... Can you explain why these are not included on the NIST list of strong lines?

This brings me to my next question. Do all of the other elements on the periodic table also have series limits that are not included on the NIST database of strong lines? If so can you point me to where I can find a list of the series limits for the rest of the periodic table? Maybe I am missing something fundamental and simple? It just seems that I can't find a straightforward answer to this question in spite of reading a lot of rudimentary articles about the emission lines. If there is a good book that answers these specific questions I would also love to know about it. Thanks so much for your time and expertise.

 

[jedishrfu]

The NIST Atomic Spectra Database (ASD) lists “strong lines”, actual discrete, measurable transitions between bound states (energy levels) where an electron moves from one level to another, emitting or absorbing a photon.

A series limit is not a discrete line; it’s the accumulation point (or asymptotic limit) where the series of lines converge as the electron gets closer to ionization.

 

[James Kahn]

The NIST Atomic Spectra Database (ASD) lists “strong lines”, actual discrete, measurable transitions between bound states (energy levels) where an electron moves from one level to another, emitting or absorbing a photon.

A series limit is not a discrete line; it’s the accumulation point (or asymptotic limit) where the series of lines converge as the electron gets closer to ionization.

Thanks this helps some. So do all elements on the periodic table have series limits or convergent points like hydrogen? And if so where can I find a list of the series limits? Also you said it is not a discrete point or line but the series limits I did find for hydrogen on wiki are single precise measured wavelengths. So I am a but confused. Thanks again for your help.

 

[jedishrfu]

It's much harder to measure the series limit on multi-electron atoms and likely of less interest than the hydrogen case because when doing the measurement you're not sure of what electron you've ionized.

 

[James Kahn]

Thanks for the reply.This makes more sense. So basically you are saying that it is not possible to measure the series limits for other elements like oxygen, carbon etc..... and the data does not exist?