In XRD analysis I am having 2 different FWHMs, one is the original data FWHM value(0.096), and after refinement, I am having different FWHMs(0.38), which I can take for crystallite size calculation. Kindly help me thank you in advance
Dear friend Atchaya Sundararajan
When calculating crystallite size from XRD analysis, it is generally recommended to use the FWHM value obtained after refinement rather than the original data FWHM value. The refined FWHM represents the peak broadening due to instrumental effects, such as the X-ray source and the instrument resolution, as well as the crystallite size contribution.
The refined FWHM takes into account the instrumental broadening and provides a more accurate estimate of the crystallite size. It helps to isolate the contribution of crystallite size from other factors that may affect peak broadening in the original data, such as instrumental broadening and sample preparation effects.
To support this recommendation, you can refer to the following research papers that discuss the calculation of crystallite size using refined FWHM values in XRD analysis:
1. Cullity, B. D., & Stock, S. R. (2001). Elements of X-ray diffraction. Prentice Hall.
2. Balzar, D., & Ledbetter, H. (1998). Size-strain line-broadening analysis of the ceria round-robin sample. Journal of Applied Crystallography, 31(3), 388-393.
3. Langford, J. I., & Wilson, A. J. C. (1978). Scherrer after sixty years: A survey and some new results in the determination of crystallite size. Journal of Applied Crystallography, 11(2), 102-113.
These references provide detailed information on the calculation of crystallite size and emphasize the use of refined FWHM values for accurate size determination.
Dear Atchaya Sundararajan ,
how can a result of a refinement give a peak width of about 4 times larger than the measurement (0,096 measured vs 0,38 refined).
There must be something wrong in the refinement fit...
In the case of such a strong disagreement I would take the measured FWHM, but corrected for the instrumental broadening...
Best regards
G.M.
Thank you Kaushik Shandilya and Gerhard Martens sir I look into it and get back to u with the answer
Note that Kaushik Shandilya's answer assumes that the FWHM given by refinement is the result of subtracting instrumental contributions, but, as GM points out, the "refined" FWHM is greater than that of the raw data, so Kaushik Shandilya's assumption cannot be correct.
Please also note that "refinement" does not directly give a FWHM (without further calculation, perhaps). So it is not clear what Atchaya is reporting.
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