Hello,
a question of general interest. How does TOPAS estimate the crystalline size of nanoparticles? How can one explain discrepancies between values TOPAS gives me and a manual assessment by Scherrer's equation?
Thanks.
TOPAS uses the peak shape to calculate crystallite size. It applies a Lorentzian and/or Gaussian convolution. However, perhaps the best measure to use is LVol-IB that calculates uses FWHM and Integral breadth to give volume-weighted mean crystallite sizes. Scherrer is simply using FWHM at a given angle. TOPAS uses full peak profile.
TOPAS uses the peak shape to calculate crystallite size. It applies a Lorentzian and/or Gaussian convolution. However, perhaps the best measure to use is LVol-IB that calculates uses FWHM and Integral breadth to give volume-weighted mean crystallite sizes. Scherrer is simply using FWHM at a given angle. TOPAS uses full peak profile.
Question : when i compare my calculation from scharrer equation and topas fitting, the result to much different. i using standard corundum (al2O3) to calculate peak at position 35.14 degree.
From scherrer equation , crystallite size : 163.80nm
From EVA , crystallite size : 162.80nm
From TOPAS : 400nm.
how to calculate correctly?
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