A Bayesian approach to extracting structure-factor amplitudes from powder diffraction data

Abstract

This paper presents a method for the reliable extraction of structure-factor amplitude information from the least-squares integrated-intensity refinement of powder diffraction data. The inevitable overlap of Bragg reflections can lead to strongly correlated reflection intensities that can, in turn, produce unrealistic negative intensity estimates. A Bayesian method is presented that tackles the problem of highly correlated positive and negative intensities. The results indicate that accurate structure-factor amplitudes may be recovered even in regions of a powder diffraction pattern where overlap is almost complete.