Single Peak Fitting Using Convolution Approach- Y2O3
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.]