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Explanation of radioactive decay

  1. Dec 16, 2008 #1
    Hi folks

    I was wondering if someone could please help me with the following:

    Is the explanation for radioactive decay (if it is not "induced") the increase in entropy, and
    is it true that an activation energy must be overcome (if so, does that mean that it is not possible for an unstable isotope to decay in total vacuum).

    Thank you very much for your help!
  2. jcsd
  3. Dec 16, 2008 #2
    Radioactive decay is a quantum tunneling phenomena...which has nothing to do with "total vacuum", whatever that means....given a number of unstable nuclei they will decay in a statistically random fashion..no one knows which nuceli will decay next....

    lots more at
  4. Dec 16, 2008 #3

    Thank you for your quick reply, I read about it in wikipedia before I came here to ask, that was where I found out about the activation energy and entropy. However, I want to ask the experts, I'm never sure about what I can trust on wiki, even though it is a very good reference.

    "Total vacuum" is a stupid way of saying "not normal vacuum, which has some particles that can interact" - so I guess "no disturbing elements" or something would be better! Haha
  5. Dec 16, 2008 #4


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    Every spontaneous process is connected to an increase in entropy, so I agree with the Wikipedia article on that point.
  6. Dec 17, 2008 #5

    Thank you for your reply! So would you say that in order for "one decay" to occur, an activation energy must be overcome, even though it is spontaneous?
    Thank you for your time.
  7. Feb 14, 2010 #6
    I have a question:
    Radioactive decay is possible in vacuum or not?
    anyone plz tell me.....
  8. Feb 14, 2010 #7

    Vanadium 50

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    Yes. Why not?
  9. Feb 14, 2010 #8
    Nearly every radioactive atom will decay in a vacuum. Some atoms decay only by capturing an atomic electron, and will (may?) be stable if all the atomic electrons are stripped off. I think that there are two stable isotopes (neutral atoms) that decay radioactively only when the nucleus is bare (no electrons), because the Coulomb field of the atomic electrons inhibit the radioactive decay of the nucleus. I think that A≈ 181 to 185. Anyone remember?

    Bob S
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