I'm using MAUD software for XRD analysis. After rietveld refinement I got sig value as 1.4. When I tried with different cif files from COD database my sig value kept on reducing. What must be the appropriate sig value?
After getting XRD spectra, it is needed to match the spectra with the JCPDS database and see which data match properly. Sometimes due to the presence of mixed phase in the sample, the match can deviate to some extent. Good luck!
I did match my Spectra with COD database. I tried 2 files. The sign value is around 1.4 for 1st one and for 2nd on it's around 1.2. Could you please tell me whether this sig value is correct or not. Also please let me know which database is more appropriate COD or JCPDS
I want recommend to use diffractogram instead of spectrum since the last one is preferred to use for correlation of a signal in dependence to energy. If you use this term it might be misunderstood, e.g. you would use white radiation...
BTW: Databases will practically never match your experimental signal. They give you some indication about the phase. All databases have errors so that it is hard to say which is better. They collect data and are not really responsible for the correctness of published data.
Dear Deepthi
The MAUD software developers argue that the acceptable sig values should be less than 2. Therefore, you can assume that your Rietveld refinment is acceptable too. However, you should also visually assess the coincidence of your diffracttion pattern with the model (e.g. missed diffraction peaks, shifts).
For more information, see the lessons at YouTube:
https://www.youtube.com/watch?v=J5aP_j-3AXI&list=PLgFhNUxDIsKCmphYhkv-HR_UduX6-9RFm&index=3
Both the COD and the JSPDS databases are acceptable, the only difference is that the COD is free.
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