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Homework Help: Form factor

  1. Mar 20, 2007 #1

    malawi_glenn

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    I have a form factor that only depends on the momentum transfer q, this is symbolised by writing the form factor as F(B]q[/B]^2).

    attachment.php?attachmentid=9529&stc=1&d=1174375818.jpg

    if i have a spherical symmetric distribution of charge, f only depends on the radius; r = | q|

    Then integration over all solid angels yields:

    https://www.physicsforums.com/attachment.php?attachmentid=9530&stc=1&d=1174376003

    (there should be a r^2 inside the integral ;))

    I do not understand how this Sinus - thing plops up.. all i know is this:
    https://www.physicsforums.com/attachment.php?attachmentid=9531&stc=1&d=1174376117

    I really need a hint how to go from the exponential function to this sinus thing. =/
     

    Attached Files:

  2. jcsd
  3. Mar 20, 2007 #2

    Dick

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    Since f(x) is independent of the polar angles you can rotate the x coordinate system so that the q vector points along, say, the positive z-axis. So the exponential becomes exp(i*|q|*r*cos(theta)). Doing the theta integration gives you the 'sinus thing'.
     
  4. Mar 20, 2007 #3

    malawi_glenn

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    thanx alot, i will try tonight:)
     
  5. Mar 20, 2007 #4

    malawi_glenn

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    it was a piece of cake now, thanx again!
     
  6. Oct 22, 2010 #5
    Could you explain more about it?
     
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