I am willing to get insights on how to perform pair distribution function analysis of powder diffraction data obtained for amorphous pharmaceutical.
I have googled and found some software packages, which can perform it.
However, getting it done using excel could provide better insights about variables within.
Can anyone suggest!
There are to the best of my knowledge 4 program packages available to calculate the PDF of a material.
PDFgui by the Billinge group does this for materials that you can describe with a periodic supercell.
A similar approach is done in the commercial Rietveld Program TOPAS by Bruker.
For materials with high degree of disorder the reverse Monte Carlo approach is used in RMCprofile.
Finally the DISCUS program suite allows any of the above algorithms.
If you look at the book by Egami & Billinge or the DISCUS Manual you will find a reasonable well documented description of the algorithm. There are no big secrets behind the codes.
A rough estimate would suggest a few thousand lines of code will do the job. You would have to implement the algorithm line by line in Excel. This will include :
interpretation of a CIF file
building a complete unit cell / supercell of unit cells
calculating all pair wise distributions
convoluting each by the appropriate thermal parameters
convoluting the properly weighted sums by the instrumental resolution function
Added a refinement script to optimize your parameters.
It could be done, I would expect a very slow code in an interpreter like Excel.
So why bother?
Dear Samarth D Thakore ,
I fear that you have to implement the appropriate functions by your own...
For a starting point you may have a look at:
https://www-ssrl.slac.stanford.edu/conferences/workshops/scatter2006/talks/hufnagel.pdf
and tutorial on pairdistribution function:
https://www.youtube.com/watch?v=NyAG_MU3jJs
good luck
Dear Dr. Gerhard Martens
Thank you so much for your response. I read the suggested material. As a primary understanding, I thought of conducting these experiments using some laboratory PXRD.
However, this makes me clear that it is not possible to do so, and even more challenging for pharmaceutical materials.
It need some synchrotron source that unavailable at my disposal, I shall try for some collaboration, if possible.
Many thanks for your response. It was really helpful.
Sincerely
Samarth
There are to the best of my knowledge 4 program packages available to calculate the PDF of a material.
PDFgui by the Billinge group does this for materials that you can describe with a periodic supercell.
A similar approach is done in the commercial Rietveld Program TOPAS by Bruker.
For materials with high degree of disorder the reverse Monte Carlo approach is used in RMCprofile.
Finally the DISCUS program suite allows any of the above algorithms.
If you look at the book by Egami & Billinge or the DISCUS Manual you will find a reasonable well documented description of the algorithm. There are no big secrets behind the codes.
A rough estimate would suggest a few thousand lines of code will do the job. You would have to implement the algorithm line by line in Excel. This will include :
interpretation of a CIF file
building a complete unit cell / supercell of unit cells
calculating all pair wise distributions
convoluting each by the appropriate thermal parameters
convoluting the properly weighted sums by the instrumental resolution function
Added a refinement script to optimize your parameters.
It could be done, I would expect a very slow code in an interpreter like Excel.
So why bother?
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