I will show how to determine the “Full width

at half maxima” by 2 different ways. The method which most of the researchers use. And then, the method which I use and I think

better. After very briefly talking about the Scherrer

equation, I will show how you can calculate crystallite

size easily. One manually writing the formula. Or, alternatively using my templates as an

automatic calculator. After plotting the data, go to analysis. Choose “Peaks and Baselines”, and then select

“Multiple Peak Fit”. Open Dialog… If you are using an older version of Origin,

you may need to enter the number of peaks. If you are new to “Multiple Peak Fit”,

I suggest you to watch my previous video on “Multiple Peak Fit”. Link is given in the description. .

Here, you have to choose the peak type. In most of the cases for XRD, Gaussian or

Lorentzian work better. I will compare both. First, I will use the Gaussian. Double click on the peaks to select them. When you are done selecting, “Open non-linear

fit”. Here, you can find tonnes of information regarding

the fit. I have to use “Fit until converge” option. Now the fit has converged at 18 iterations. It may go more than even 100 if there are

several types of peaks and noisy background. Click OK as it is completed. Let’s have close look,

How well it is fitted. At lower, around the background,

the peaks are not fitted well. However, you can still use it,

as we are concerned about the full width at half maxima. Let’s check it with Lorentzian shape. Resizing for better visibility. Adjusting the scale though it is not very

important. Now I have to choose Lorentz here. This is better than the previous fit. Up to now, I have shown how it is done most

of the researchers. But, I suggest you to use the following method. Instead of using multiple peak fit, use quick

fit. Go to Gadgets. Then Quick fit. Choose “Peak – Lorentz” as we know Lorentz

fits better. Now, you have to just magnify the peaks one

by one. First, do for the first peak. Looks good. If necessary,

You can adjust the highlighted region by dragging the sides. Find the fitted parameters from here. Keep only values, separated by single space. Select all. Copy them. Cancel the change, as we have copied already. Make a new sheet. Write the parameters and units. Paste the copied values. Repeat the steps for other high-intensity

peaks. W represents the Full width at half maxima. We have extracted values from 5 peaks. For calculation of crystallite size,

3 to 5 peaks will be okay. In the next half, I will these values to calculate

crystallite size. Before, doing that let’s know the important

basics. This is the Scherrer equation. L is crystallite size which we want to calculate. All angles are in radian. K is constant. In most of the cases for spherical crystallites,

you can use 0.94 or close to 1. So, the formula you have to insert in Origin

or Excell is this. Let’s do it. The first column is for K.

Second is Lambda in Angstrom. Peak position, 2 theta.In degree. Half-width at full maxima. in degree. Last column for calculated crystallite size. in nanometer. I am using K as 0.94. The wavelength of X-ray as 1.54178 angstroms. These are constant for all peaks. Copy and paste calculated values. Now carefully enter the formula. First column, K.

Multiplication. Second column, Lambda. Division. Radians of FWHM. Division. Cos of peak position. In radians. As it is 2 theta, divide by 2. For Angstrom to nanometer divide by 10. Close the brackets. Press ok. You got the crystallite size. Seems preferential growth of crystallite. Or could be a technical problem. If you see such difference, ignore the low-intensity

peaks. Now alternatively,

You can download these templates from the link given below. In both these Excel or Origin, I have inserted

the formula. You just have to paste the values from

the full width at half maxima calculation.

Hi. I tried analyze my XRD data. After picking up the peak, and try to "Fit till Converge", The last message says "Fit did not converge".. So, what should I do?

You are the champ.

Foi de grande ajuda este tutorial! Muito obrigado por compartilhar seu conhecimento. Thanks to share your knowledge!

Instrumental brodening needs to be subtracted.

Thank you so much for your video. It helped me a lot! 😊

FWHM should be multiply with cos theta, right?

Isn't it should be:

(Col("K")*Col("λ"))/radians(Col("FWHM"))*cos(radians(Col("Peak Position 2theta"))/2)/10

instead of:

(Col("K")*Col("λ"))/radians(Col("FWHM"))/cos(radians(Col("Peak Position 2theta"))/2)/10

Please correct me if I'm wrong. TQ

Thanks a lot it is working sir…..