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Homework Help: Photoelectic cross-section question

  1. May 19, 2008 #1
    1. The problem statement, all variables and given/known data
    Show that if we consider photoemission from the 1s state of a charge Z atom,
    [tex]
    \sigma \propto Z^5}}
    [/tex], in the limit [tex] p_fa_0/Z\hbar >> 1.
    [/tex]


    2. Relevant equations

    [tex]
    \sigma = \frac{128a_0^3\pi e^2p_f^3}{3m\hbar^3\omegac[1+p_f^2a_0^2/\hbar^2]^4}}
    [/tex]



    3. The attempt at a solution
    Actually I know how to do this. [tex] a_0 -> a_0/Z [/tex]. My question is why is this so? What is the physical interpretation/what does it mean?

    jsc
     
  2. jcsd
  3. May 19, 2008 #2
    I think the reason [tex] a_0 -> a_0/Z [/tex] is because the Coulomb potential in the Hamiltonian changes from [tex] q^2/r [/tex] to [tex] Zq^2/r [/tex]. Is that right?

    jsc
     
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