Larch for XAFS Analysis 7: Background subtraction

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  • เผยแพร่เมื่อ 4 ม.ค. 2025

ความคิดเห็น • 3

  • @eugenesys
    @eugenesys 2 ปีที่แล้ว

    Hi Matt, thanks for the videos, Larch is pretty nice.
    I would like to understand more about the k-weight in the R-space, any suggestions about it?
    Best regards.

    • @MatthewNewville
      @MatthewNewville  2 ปีที่แล้ว

      @eugenesys I am not sure that I understand the question. When doing a Fourier transform for EXAFS data, one typically multiplies chi(k) by k^n which typically called "k-weighting". It does alter the Fourier transform chi(R), but in a predictable way. Common values for n are 1, 2, or 3.
      When doing background subtraction, we do use a Fourier transform to separate low and high R-regions (with Rbkg being the cutoff). Since we are doing a Fourier transform, we can pick a k-weight, but for background subtraction using n=0 or 1 usually works best, and using n=2 is rarely better than n=1.

    • @eugenesys
      @eugenesys 2 ปีที่แล้ว

      @@MatthewNewvilleThanks! Ok got it.
      I misunderstood there is a correlation between the atomic number of the atoms and the k-weight.