Understanding FWHM in XRD Analysis of Powder Patterns

In summary, FWHM stands for full width at half maximum and is a measure of the width of a peak in an XRD powder pattern. It is calculated by measuring the distance between the points on either side of the peak where the intensity is half of the maximum intensity, and can be influenced by various factors such as the size and shape of the crystalline particles, degree of crystallinity, and instrumental broadening. Understanding FWHM can provide information about the crystalline perfection of a material, and it can also be used as a qualitative tool to identify different phases in a sample.
  • #1
VASUbhagwat
14
0
Why is FWHM taken for calculations in XRD analysis of powder pattern? I mean, why don't we take the full peak value?
 
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  • #2
They are two different things. The peak value gives you the height of the distribution. The FWHM gives you a measure of the width of the distribution.
 
  • #3
Thanks a ton for your reply . But what i want to know is why do we take the width for calculations and not the height
 
  • #4
For what kind of calculations? Can you give an example?
 

1. What is FWHM in XRD analysis?

FWHM stands for full width at half maximum and is a measure of the width of a peak in an XRD powder pattern. It is a metric used to quantify the degree of crystalline perfection in materials.

2. How is FWHM calculated in XRD analysis?

FWHM is typically calculated by measuring the distance between the points on either side of the peak where the intensity is half of the maximum intensity. This distance is then multiplied by 2 to get the full width at half maximum.

3. What factors influence the FWHM in XRD analysis?

The FWHM in XRD analysis can be influenced by various factors such as the size and shape of the crystalline particles, the degree of crystallinity, and the instrumental broadening caused by the X-ray source and the instrument itself.

4. How does understanding FWHM help in XRD analysis?

Understanding FWHM can help in XRD analysis by providing information about the crystalline perfection of a material. A smaller FWHM indicates a more perfect crystal structure, while a larger FWHM suggests imperfections or defects in the crystal lattice.

5. Can FWHM be used to identify phases in a sample?

Yes, FWHM can be used as a qualitative tool to identify different phases in a sample. Each phase will have a unique FWHM value, and comparing the FWHM values of different peaks in a pattern can help identify the presence of different phases in a sample.

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