Understanding FWHM in XRD Analysis of Powder Patterns

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FWHM (Full Width at Half Maximum) is used in XRD analysis of powder patterns because it provides a more reliable measure of peak broadening, which is essential for determining crystallite size and strain. Unlike peak height, which only indicates intensity, FWHM reflects the distribution's width, offering insights into material properties. Calculations such as the Scherrer equation utilize FWHM to estimate crystallite size, making it a critical parameter in characterizing materials. The focus on width rather than height allows for a more accurate representation of the sample's structural characteristics. Understanding FWHM is crucial for effective analysis in XRD studies.
VASUbhagwat
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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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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.
 
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
 
For what kind of calculations? Can you give an example?
 
Thread 'Unexpected irregular reflection signal from a high-finesse cavity'

Thread 'Unexpected irregular reflection signal from a high-finesse cavity'

I am observing an irregular, aperiodic noise pattern in the reflection signal of a high-finesse optical cavity (finesse ≈ 20,000). The cavity is normally operated using a standard Pound–Drever–Hall (PDH) locking configuration, where an EOM provides phase modulation. The signals shown in the attached figures were recorded with the modulation turned off. Under these conditions, when scanning the laser frequency across a cavity resonance, I expected to observe a simple reflection dip. Instead...
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