Application of symmetrized harmonics expansion to correction of the preferred orientation effect

In powder diffraction measurements, the errors in integrated intensities caused by preferred orientation can be corrected by using some suitable analytical model as the representation of the orientation distribution of the crystallites. In this paper, a model based on symmetrized harmonics expansion is described in detail. The harmonic functions in different crystal symmetries are given and the influences of various diffraction geometries are examined. Applications of the method in quantitative phase analysis and particularly in the Rietveld method are described. The method is clarified using corundum as an example.