research papers
A new procedure to perform quantitative analysis without any internal standard has been developed within Rietveld analysis. This new approach permits solution of the problem due to the presence of an amorphous phase when its chemical composition or the global sample composition is known. The equations developed, based on a study of the global intensities diffracted by each phase in reciprocal space, reduce to the well known formula of Hill & Howard [J. Appl. Cryst. (1987), 20, 467-474] when applied to completely crystalline materials.