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Absorption of a Photon

  1. Sep 8, 2011 #1
    How is a photon absorbed by an electron? Do the constituents of an electron have any role to play in this?

    Suppose the edge (boundary) of a photon approaches the edge (boundary) of an electron ( this image is just for convenience). What happens next? Does some kind of attraction develop between these two?
  2. jcsd
  3. Sep 9, 2011 #2


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    I think the best description of what actually happens is given by quantum electrodynamics, but essentially, the photon gets close to an atom, then it suddenly disappears, and the atom goes into a higher orbital.

    Also, the photon doesn't go inside the electron. What happens is the photon ceases to exist, and the electron then exists in a higher orbital. (in other words, the electron has no constituent parts).

    You were asking about whether some attraction happens. Well the photon doesn't have a charge, so not really. There will be some probability that the photon is absorbed (and this probability will be given by quantum electrodynamics).

    Also, the photon and electron don't necessarily need to get very close to each other for the electron to absorb the photon.
    As another example: when a nucleus emits an alpha particle, the alpha particle 'tunnels' out of the nucleus. So this means that at one stage the alpha particle is inside the nucleus, then it will be some small distance from the nucleus, without having existed closer to the nuclues.
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