Definition and application of sharpness parameters for powder diffraction peak profile

Abstract

Powder diffraction peak profile with both sharpened peak-top and long tail is often observed, when the collection of small crystallites has broad size distribution. Recent theoretical studies on such diffraction peak profiles have revealed that the sharpened peak profile is naturally expected to be observed for broad size distribution of crystallite size. Analytical method to evaluate the distribution of size as well as the average size have been proposed, which can be easily applied by using a curve fitting procedure. In this study, the author proposes new definitions of sharpness parameters and compares with the known parameters. Validity of a convenient method applying approximate peak profile models will be discussed.