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Excited atom decaying to ground state

  1. Nov 28, 2006 #1
    I'm trying to grasp this concept. The question states:
    An excited atom decays to its ground state and emits a photon of green light. If instead the atom decays to an intermediate state, what color of light might be emitted?

    I have the electromagnetic spectrum with the visible lights broken down.
    Am I supposed to understand that an atom decaying to an intermediate state wouldn't use as much energy as an atom decaying to ground state?
    Something like E = hf. So because of the decrease in energy, there is an increase in frequency, so the emitted light might be Blue or Violet, which have higher frequencies than green?

    Am I on the right track?


  2. jcsd
  3. Nov 28, 2006 #2


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    Nope, if it decays into an intermediate state, then the energy gap b/w the levels will be smaller, hence the frequency of the radiated photon.

  4. Nov 28, 2006 #3
    Ohh okay.
    So the CHANGE in energy between the excited state and intermediate state is smaller than the change in energy between the excited state and the ground state.

    So the equation: Change in energy = h * f provides:
    A smaller change in energy creates a higher frequency photon.
    Violet and blue have higher frequencies than green.
    Therefore, the emitted light would be violet or blue.

    Thank you.
  5. Nov 28, 2006 #4


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    No way, if the energy is smaller, then the frequency would be smaller, since they are directly proportional. So i'd say rather yellow or orange.

  6. Nov 28, 2006 #5
    Ohhhh.. okay.
    I don't know how I didn't see that.
    Becuase h is Planck's constant, difference in energy is proportional to frequency.. so it would be a lower frequency photon.. like red or orange..
    Got it..
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