PDF analysis on X-ray data from lab-based Rigaku Smartlab XE

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Rasmus Tang

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Oct 2, 2024, 5:01:13 PM10/2/24
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Dear DiffPy community

I am about to embark on my first ever PDF journey, and I was hoping you could give me some advice on how to treat my data before fitting G(r). I have measured powder diffractograms using a Rigaku Smartlab XE with Mo k-alpha radiation. The sample was contained in a spinning Kapton capillary.
  1. I have already subtracted the signal of an empty capillary. Are there other secondary scattering / absorption features I can correct for?
  2. Is there a reliable way to correct for K-alpha splitting before I convert to G(r)? I plan on using PDFgetX3, which only takes one wavelength as input.
Any advice you can give on getting G(r) from a lab-based pXRD would be greatly appreciated!

Sincerely,
Rasmus Tang Christiansen
Postdoctoral Fellow
Mourigal Lab | School of Physics 
La Pierre Group | School of Chemistry and Biochemistry
Georgia Institute of Technology

Simon Billinge

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Oct 2, 2024, 6:00:54 PM10/2/24
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Dear Rasmus,

We are working on exactly this problem (analyze Mo lab-data using pdfgetX3).  Please can you reach out directly to me (sb2...@columbia.edu) and I can put you in touch with the team of students working on this.. 

For everyone in general, PDFgetX3 will process lab data to get a nice PDF, no problem, but a key assumption behind the algorithm is violated in many cases, that of negligible absorption, so although the PDF you get will look good, it will be wrong.  We are working on a fix for this.  Please stay tuned.


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Simon Billinge
Professor, 
Department of Applied Physics and Applied Mathematics
Columbia University

Wanuk Choi

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Jan 27, 2025, 11:23:26 PMJan 27
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Hello. I just wrote about G(r) not being correct when calculating coordination number using Lab Mo X-ray, and then I saw this article that said negligible absorption could be a problem. Could my situation be similar?

https://groups.google.com/g/diffpy-users/c/dckgbGgHAPE/m/qlq6KZAIDwAJ

2024년 10월 3일 목요일 오전 7시 0분 54초 UTC+9에 Simon J. L. Billinge님이 작성:
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