X-Ray Diffraction Phase Analysis

Jaroslav Fiala

New Technologies - Research centre, University of West Bohemia in Pilsen, Univerzitní 8, 306 14 Plzeň

The determination of phase composition is one of the most frequnetly used applications of X-ray diffraction. It is based on comparison of powder diffraction pattern of analysed compound with the database of reference diffraction patterns. Ordering of the database and the way how it is used for the determination of phase composition determine the efficiency of qualitative phase analysis. Methodic development of this discipline can be based on the mathematical model of X-ray diffraction identification which is build on the basis of linear algebra. This model also theoretically explains the reasons of practical difficulties encountered at the analysis of phase composition of multi-component mixtures. And it is also a base for overcoming of these difficulties and successful identification of complicated mixtures by factor analysis of their diffraction patterns.

Quantitative determination of the phase abundances in mixtures of crystalline substances belongs to the most important applications of x-ray powder diffraction. The crucial point of this technique consists in the calibration procedures which are described and elucidated in detail in this paper. Another important issue, the uncertainty of the results of the quantitative powder diffraction phase analysis, is discussed thoroughly, too, along with the sources of this uncertainty and the means by which the uncertainty can be reduced.

Full papers will be published