Influence of Texture on Powder Diffraction

Abstract

Classical Powder Diffraction usually assumes samples with completely random orientation distribution of the crystallites. It can be generalized to non-random orientation distribution (texture) by introducing a texture factor which enters the expression of the integral intensity directly and serves as a weight function in expressions of peak shift or peak broadening. Hence, all methods of powder diffraction, for instance, phase analysis, crystal structure analysis, stress analysis, particles size analysis, can also be carried out with textured samples.Textured polycrystalline samples may be considered as being intermediate between single crystals and random powder samples. Hence, they contain information about the directions of reciprocal lattice vectors r(hkl)∗ which are “averaged out” in random polycrystals, the measured intensities of which depend only on the absolute values |r(hkl)∗|. This information can be used, for instance, to separate overlapped structure factors |F(hkl)|2 or to index powder diffraction diagrams.