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I Peak profile fitting in X-ray Crystallography, why Voigt?

  1. Feb 5, 2017 #1
    Hi,I've been doing a lab cycle on X-ray crystallography. We are using Cu X-ray source on chloride salt crystals. It seems that the Bragg peak profile are commonly acknowledged to be a Voigt function, which is a convolution of Gaussian and Lorentzian. I am wondering what's the physical reason for this. What causes the Gaussian spread and what leads to the Lorentzian component?
     
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  3. Feb 6, 2017 #2

    Andy Resnick

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    Gaussian lineshapes are due to inhomogeneous broadening mechanisms (Doppler, local strain, etc), while Lorentzian are due to homogeneous broadening mechanisms (collisions, pressure broadening etc).
     
    Last edited: Feb 7, 2017
  4. Feb 7, 2017 #3
    And is there an explanation for skewness of the peaks?
     
  5. Feb 7, 2017 #4

    Andy Resnick

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    No clue. Don't know of one.
     
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