Digitized Database Quantification, DDBQ, Analysis of Complex Mixtures using Fully Digitized Patterns

Use of the fully digitized X-ray diffraction pattern for phase quantification has proven to be the most effective approach to achieving the theoretical accuracy potential of 1 % absolute. The digitized database quantification technique, DDBQ, was developed in the 1980s. Appropriate reference patterns are stored in small databases and selected for fitting to an experimental pattern of a mixture. The reference patterns may be experimental, calculated from crystal structure information, or simulated from d-1 lists. A least-squares fitting procedure of the selected patterns to the experimental data provides a reference pattern scale factor that is converted to weight fractions of the phases by employing the reference intensity ratio. Comparisons with the Rietveld method on the same experimental mixture patterns verify that the same levels of accuracy are achieved by both methods.