XRD Data Analysis Question

  • #1
47
5
The major diffraction peaks of my sample have essentially the same 2θ values as the reference (graphically), but have different heights. Can it still count as conclusive evidence that my sample matches the reference? Or does it suggest that my sample is a different substance?

Also, as a side question, can you suggest any good, up-to-date and free reference text books (or any other sources) that I should read up to master XRD analysis? The one I'm reading right now is from 1956.

I'm kind of new to the research field. I would really appreciate your help.

Thanks!
 

Answers and Replies

  • #2
229
2
Its tricky to do. There is a process called Rietveld refinement that can help separate patterns. Programs like Topas are also quite good at doing this. You may have to rely on minor peaks if your reference pattern is in the same Laue pattern as your data.

If the 1956 book is by Cullity, its still very good. The updated version (cullity and stock) is the one I use.
 
  • #3
Baluncore
Science Advisor
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Can it still count as conclusive evidence that my sample matches the reference? Or does it suggest that my sample is a different substance?
They are not the same.

If I remember correctly from the 1970s, the 2θ values are a function only of the shape and size of the cell.
The density of the peaks is dependent on which sites in the unit cell are occupied by which atoms / elements. So different peak heights to the reference means different chemistry with the same size unit cell.
 

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