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Homework Help: Mossbauer Effect in Iron-57

  1. Mar 6, 2012 #1
    1. The problem statement, all variables and given/known data
    Calculate the Doppler velocity needed to compensate for the recoil energy.

    2. Relevant equations
    [itex]V=\frac{E_{0}}{m c}[/itex]

    3. The attempt at a solution
    I found the recoil energy to be [itex]1.95\times10^{-3}[/itex] eV.
    And for Iron-57, [itex]E_{\gamma}[/itex] is 14.4KeV. Which is approximatly equal to [itex]E_{0}[/itex].
    So just plugging these values into the above equation, I get 81.27m/s which seems a bit high, as many articles site around 10mm/s!

    Perhaps units I am using should be in something else? Or maybe I am using the completely wrong equation?
  2. jcsd
  3. Mar 7, 2012 #2
    From the wiki: http://en.wikipedia.org/wiki/Mössbauer_effect

  4. Mar 7, 2012 #3

    Ohhh..... and of course I'm calculating it for a "Free" atom, not one bound in a solid! So the higher velocity makes sense!

    Thank you so much for the help!
  5. May 10, 2012 #4
    You answer for recoil velocity seems to be correct (i get 81.47 m/s). The 10 mm/s velocity is not the recoil velocity. It is the speed of transducer, i.e. the vibrating velocity of the Mössbauer source to acquire a complete Mössbauer spectrum..1 mm/s is equal to 48.075 neV ([itex]E_{D}=\frac{E_{\gamma} v}{c}[\itex], take v=1 mm/s and you will get 48.075 neV).
    Cheers, Rajini
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