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Isotope EV & HL

  1. Mar 5, 2004 #1


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    I was looking at a http://chemlab.pc.maricopa.edu/periodic/isotopes.html and was wondering why the half-life was sometimes replaced with electron volts? There's an example from the table below:

    Code (Text):

    Helium-6    806.7 milliseconds   -> Lithium-6
    Helium-7    160 KEV              -> Helium-6
    Helium-8    119.0 milliseconds   -> Lithium-8
    Helium-9    0.3 MeV              -> Helium-8
    Helium-10   0.3 MeV              -> Helium-9
    Last edited by a moderator: Apr 20, 2017
  2. jcsd
  3. Mar 19, 2004 #2
    In the examples you've shown, the ones denoted by an energy decay rapidly via neutron emission. This happens on timescales on the order of femtoseconds or less. The value for the energy comes out of the uncertainty relationship. Effectively "Energy * time < h-bar", where 'h-bar' is planck's constant. If you solve the equation for time using the energy value given and Planck's constant, you get a value for the time of the decay.

    Sorry for not being able to use all these cool board features to make it a nicer presentation.
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