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Photon/atom interaction

  1. Dec 29, 2015 #1
    Ok, i want to make the question clear:
    1) Let's say I strike my hydrogen atom with a single photon; will the electron rise up a shell level, and the nucleus become more energetic as well? OR just the electron will rise up a shell level, and the nucleus will be undisturbed?
    2) Also, if I strike a hydrogen ion; just a proton, with a photon, will the proton become more energetic, meaning a volume of which will experience a rise in temperature?
  2. jcsd
  3. Dec 29, 2015 #2


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    Pretty much the latter. The nucleus will remain in its ground state since nuclear transitions require MUCH larger energy scales than electronic transitions.

    No, the ion would just be accelerated. It would take a high-energy gamma-ray photon to induce a nuclear transition. Also, temperature doesn't really apply to a single proton.
  4. Dec 29, 2015 #3
    Thanks. But in regards to the temperature, should there be a volume of such protons in a fixed vessel, bombarded with photons, wouldn't that imply a rise in temperature?
  5. Dec 29, 2015 #4


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    None of the two. The energy levels are a property of the whole atom. The nucleus is much heavier, so the change affects the electron more than the nucleus, but describing the process just with the electron does not work. The nucleus itself does not change, and the electron itself does not change either (it keeps its mass and so on).
    It would increase the temperature in the box (on average, or with many photons). Individual particles do not have a temperature.

    Please start new posts for new questions, the thread was from 2013. I'll split the threads.
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