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Emission Spectra: which electrons?

  1. Oct 9, 2009 #1
    I am a newbie to the forum and impressed by the breadth and depth of the material here. After searching I am unable to answer a question that I have been pondering.

    One of my brightest students asked whether electrons other than the valence electrons were involved in the emission spectra of complex atoms.

    Research in my own texts didn't reveal an answer, nor did research here or on the net. The closest I got suggests that spectra are usually but not always generated by transitions of the valence electrons.

    http://www.daviddarling.info/encyclopedia/E/energy_level.html
    http://www.800mainstreet.com/spect/spectrum.html

    Can anyone confirm that spectra are generated by electrons other than the valence electrons? Any net references would also be appreciated.
     
  2. jcsd
  3. Oct 10, 2009 #2
    Hello Elly, as far as I can recall valence electrons can cause lines in the infra red, visible and ultraviolet regions of the spectrum but in more energetic regions other electrons get involved.I am thinking in particular about the characteristic lines superimposed on the continuous spectrum from an X ray tube these lines being caused by electron transitions between shells.The Gamma spectrum from certain radioactive materials is caused by nucleon transitions within the nucleus.I am pretty rusty on this stuff and hopefully others will pop in to inform us both.:smile:
     
  4. Oct 10, 2009 #3
    Hi, i am not exactly proficient in this area and i would greatly appreciate anyone that can correct me if my discussion is wrong so here's what i think.

    I remembered that for electron(s) to be excited to another quantum level, the energy of the light ray/beam(seriously have no idea the difference between ray and beam hope someone can enlighten me :biggrin:) have to have the exact energy say between n quantum level and i quantum level? So that would mean that when an atom receives energy only electrons from n quantum level will be promoted to i quantum level and no other electrons from other levels will be excited correct? If that is the case can we conclude that excitation is not limited only to the valence electrons?
     
  5. Oct 10, 2009 #4
    I think photons would be the most appropriate word to use in this context and what you have described here seems to make sense electrons other than valence electrons becoming involved particularly when we go into the higher frequency end of the spectrum.With photon excitation one might expect to be able to observe an absorption spectrum.
     
  6. Oct 12, 2009 #5
    Thank you Dadface. Your reply was much appreciated. And thanks to all who considered my question.

    Does anyone have any online references they can point me to covering this area?
     
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