Single Peak Fitting Using Convolution Approach- Y2O3

Files needed: conv_joy_01.inp, y2o3_fwhm_01.xye

Learning Outcomes: This tutorial will introduce you to convolutions and how they influence peak shapes in powder diffraction.

Information: Data were "collected" on a diffractomer with Cu Ka1 radiation on a sample of Y2O3. The monochromator angle was 27.26, the tube filament was 12 mm long, the sample was 15 mm long, 5 degree primary and secondary Soller slits were used. The 332 nm crystallite size gave a Lorentzian and the 0.05 % strain a Gaussian broadening contribution.

1. Go to the "joy of convolution" web page and have a play with different convolutions.

2. File conv_joy_01.inp will let you try different convolutions for fitting peaks as in lecture.

3. Try first hat @ 0.01, then 2 hats, then 4 hats.

4. Try gauss_fwhm @ 0.01.

5. Try lor_fwhm @ 0.01.

6. Try 4/5 together.

7. Add a circles_conv @ -0.1

8. Comment out the line "#define try_convolutions" and you'll then use the full fundamental parameters approach.

 

[Modified 31-Jul-2017 by John S.O. Evans. Pages checked for Google Chrome.]