cross-posting this on behalf of Farman Sayem

[Simon J. L. Billinge]

To: diffpy-dev

Cc: 
Bcc: 
Date: Sat, 16 Nov 2024 20:37:15 -0800 (PST)
Subject: Assistance with Refining Two-Phase PDF Data Using diffpy.pdffit2

Hi everyone,

I am an undergraduate research student working on my senior thesis, analyzing Pair Distribution Function (PDF) data for a two-phase mixture of LaB6 and CeO2. Using PDFGUI, I was able to iteratively optimize the two phases and obtain a fit. However, I want to visualize the experimental and fitted data alongside the residuals in Jupyter Notebook to highlight how each phase contributes to the mixture’s structure.

I came across an example in the diffpy.srfit GitHub repository (https://github.com/diffpy/diffpy.srfit/blob/4edfa967679ac13ad69e6558eac1bb4b96c07926/doc/examples/crystalpdftwophase.py) that uses diffpy.srfit and diffpy.srreal for this purpose. Unfortunately, diffpy.srreal is compatible only with Python 3.7, while I am working in a Python 3.10/3.12 environment with diffpy.pdffit2. Since PDFGUI is built on the diffpy.pdffit2 engine (as noted in the paper PDFfit2 and PDFgui: Computer Programs for Studying Nanostructure in Crystals), I believe it should be possible to refine and correlate two phases using diffpy.pdffit2. However, I could not find any examples or guidelines for refining multiple phases with diffpy.pdffit2.

Could anyone provide guidance or examples on how to set up and refine multiple phases using diffpy.pdffit2? Specifically, I am looking for instructions on how to correlate the phases and perform the refinements from scratch.

I would greatly appreciate any help or suggestions!

Thank you in advance. Have a great weekend.

Best regards,
Farman H. Sayem