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Homework Help: Excited helium

  1. Feb 14, 2013 #1
    I have an exercise with the following text:

    Suppose you put both electrons in a helium atom into the n=2 state. What would the energy of the emitted electron be?

    I have attached the solution to the problem, but I am not sure I understand it. I understand the first part about the total initial energy. But I don't understand what follows. If the energy of each electron is E1 and one electron drops to a state below then shouldn't it only lose a portion of energy while leaving the other electrons energy unchanged?
    Maybe I am thinking too clasically and should think of it as a total quantum system. But it is just weird for me that the electron can gain energy through the other jumping down - how is this energy transferred? (maybe too classical again) - and most importantly, why are we not considering the fact that the energy jump will cause a photon to be emitted like in the hydrogen case?

    Attached Files:

  2. jcsd
  3. Feb 14, 2013 #2


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    When one electron jumps to the ground state it must give up energy in some way. One way is the emission of a photon. But in this problem it is assumed that the energy is given directly to the other electron causing it to be ejected. This is called the Auger Effect . I agree that the process is hard to imagine classically. (But so is the emission of a photon, to me anyway. :smile:)
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