Talk:Spectral line

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A new spectral line intensity formula for optical emission spectroscopy was presented by Dr:s Bo Thelin (experimental physicist) and Sten Yngström (theoretical physicist) at the beginning of the 1980:s. This formula has shown very good agreement between experiments (Ref 1) and the new theory (Ref 2). These references are summaries of earlier papers.

I = K \ left (frac { v^2 }{ c^2 }\ right ) \ e^left (\ frac { -J}{ k \ T \ right )} \ \ left (\ e^left ( \ frac { h \ v }{ k \ T \right - \ 1)^-1

K includes transition rates and element concentrations I= spectral line intensity, v= frequency , J=ionization energy and T=temperature

Many independent experimental methods strongly support the new formula, while the standard intensity formula with the Boltzmann term (upper energy level), deviates very much from experiments. Ref 1 Yngström,S. and Thelin,B. Applied Spectroscopy, 44, 1566, (1990) Ref 2 Yngström,S. International Journal of Theoretical Physics,Vol.33, No 7,(1994)--79.138.179.27 (talk) 21:40, 10 March 2008 (UTC)

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Contents 1 Zeeman Effect 2 Isomer shift 2.1 ========== 3 Photon Cascade 4 collision broadening 5 Gaussian broadening 6 Doppler Broadening

[edit] Zeeman Effect

What about the Zeeman Effect on spectral lines? Korandder 09:24, 1 August 2007 (UTC)

[edit] Isomer shift

Isomer shift is the displacement of an absorption line due to the absorbing nuclei having different s-electron densities from that of the emitting nuclei.

Shouldn't that paragraph be in the section below that's about broadening and shifting? It seems very out of place where it is.

Also I don't understand what it's saying. It needs more explanation.

[edit] ==========

Does anyone know how easy it is to see these spectral lines? For instance, if I have a simple prism and I use it to see the sun's spectrum, can I observe a few lines with the naked eye?

Looking at the sun, probably not, but looking at a high-intensity street light, you certainly can see the lines of the evaporated metals in the lamp.Paul Reiser 01:11, 23 Dec 2004 (UTC)

[edit] Photon Cascade

The revision by 84.194.165.197 read:

...photon is absorbed. Then it will be spontaneously re-emitted, either in the same frequency as the original or in a cascade (even multiple of the original photon frequency), where the sum of the energies of the photons emitted will be the same as the energy of the one absorbed.

This can't be right. If the sum of the energies of the emitted photons equals the energy of the original photon, then each of those energies must be less than the energy of the original photon. The energies (and therefore the frequencies) of the emitted photons can't be even multiples of the original photon energy or frequency. I don't know enough about photon cascades to correct this statement, however, so I hope 84.194.165.197 will correct it. Paul Reiser 18:42, 8 Jan 2005 (UTC)

[edit] collision broadening

isn't there missing something? I tought collision broadening was the predominant effect in all chaotic light sources e.g. in spectral lamps. (see Loudon, R: The Quantum Theory of Light. 3rd edn. Oxford Science, 2000. p. 76: "The dominant effects in the majority of experiments are the Doppler and collision broadening, and the latter is used (...) to model the typical features of a chaotic light source.") Or is this an article about plasma-related stuff only? any comments? —The preceding unsigned comment was added by Joerglwitsch (talk • contribs) 13:32, 19 February 2007 (UTC).

[edit] Gaussian broadening

A couple of articles mention Gaussian broadening and there seem to be a fair number of papers which mention the term. Should this be included in the list here? --Salix alba (talk) 21:55, 6 April 2007 (UTC)

I think this means any broadening mechanism which produces a Gaussian lineshape. Doppler broadening gives a Gaussian profile, as does natural broadening. Broadening is better classified by the physical phenomenon which causes it rather than the lineshape it produces. PAR 08:09, 7 April 2007 (UTC)

Thanks for that. I've changed Gaussian broadening appropriately. --Salix alba (talk) 09:45, 7 April 2007 (UTC)

I'm a bit mystified by this discussion. In chemistry a Gaussian line-shape(or something close to it) is common, for example in UV/vis spectra of compounds in solution. Furthermore, in decomposing a composite spectral band into component bands all sorts of line shapes have been used including Gauss-Lorentz sum and product funtions. There is also the fact that an observed line shape is a convolution of the "true" line-shape with an instrumental function, such as the finite slit function. Maybe there should be a separate article on line-shape, from the experimentalist's point of view, while this article concentrates on physical mechanisms of line-broadening? Petergans 08:43, 8 April 2007 (UTC)

[edit] Doppler Broadening

I think the section on Doppler Broadening could be stated a little more clearly. It says that the motion of particles causes a Doppler shift of the emitted radiation. The section then switches to talking about the bulk effects of this, which results in broadening and no shift. I don't think the transition from the single particle to bulk effects was clearly noted. I read it three times before I understood what it meant in saying it causes a shift and doesn't cause a shift. --TonyB 2005/05/02 —The preceding unsigned comment was added by 128.233.98.29 (talk) 15:14, 2 May 2007 (UTC).