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Guessing decay modes

  1. Feb 6, 2015 #1
    how can we guess the possible decay modes for an element with three given quantities: A, Z and mass difference in MeV
  2. jcsd
  3. Feb 6, 2015 #2


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    Mass difference to what?
    You can check the masses of the nuclides that would be produced from the different decay modes, and see if such a decay is possible.
  4. Feb 6, 2015 #3


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    I assume "mass difference" means "mass defect", i.e. the difference between the mass of the nucleus and its component nucleons (when unbound)
  5. Feb 6, 2015 #4


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    Knowing A and Z and some logic will get you a very long way - the link below is a nuclear chart, coloured by decay mode. For example, a nucleus that is on the proton rich side of stability and of intermediate mass will decay in such a way that brings it closer to the valley of stability - a proton will have to turn into a neutron, so that element will probably decay via B+.

  6. Feb 7, 2015 #5
    i was taught too the equation of mass difference of calculating the difference between the initial and final masses of the nuclides, but in the question that i was given only one element was mentioned, i got confused over there. for eg mass difference of hydrogen(A=1,Z=1)= 7.289 MeV, mass difference of Nb(A=92, Z=41)= -86.448 MeV, mass difference of Rb(A=92, Z=37)=-75.12MeV

    Or can we just ignore the mass difference data and calculate the neutron-proton ratio and compare it to the valley of stability?
  7. Feb 7, 2015 #6


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    You can look it up, if necessary.
    To get a rough estimate, yes, but it won't work for every isotope.
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