Analysis of peak shapes in X-ray diffractometry (GUINIER geometry) of standard materials using asymmetric profile functions

X-ray diffraction peaks of α-AI₂O₃ (NIST-Standard No 679) and Si obtained in the asymmetric transmission mode of the GUINIER geometry are fitted with asymmetrized functions. Best fits are obtained with an asymmetrized pseudo-VOIGT function. The fitted parameters (FWHM and asymmetry) for each component (gaussian and lorentzian) and their mixing coefficient show systematic trends against the diffraction angle 2θ. The applied function is found to be well suited for fitting strongly asymmetric peaks measured on a GUINIER diffractometer.