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Average energy of atoms in the Stern–Gerlach experiment

  1. Mar 5, 2010 #1
    I have been reading about the Stern–Gerlach experiment and found that the atoms leaving the oven in the experiment have an average energy of 2kT, rather than an energy of 3kT/2 for a gas. I can not find a reason for this higher energy myself and would like suggestions on why this seems to be taken for granted on many reports I have read, and why it is so.


  2. jcsd
  3. Mar 5, 2010 #2
    It is because the atoms effuse out of the oven. Effusion should be covered in an undergrad kinetic theory course. The speed distribution in the beam is
    [tex]\propto v^3exp(-mv^2/2kT)[/tex]
    rather than the usual
    [tex]\propto v^2exp(-mv^2/2kT)[/tex]
    for Maxwell-Boltzmann.
  4. Mar 5, 2010 #3
    Thank you for the reply, I shall go read more about effusion.
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