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correspondence
The Scherrer equation versus the DebyeScherrer equation
To the Editor X-ray diraction is a convenient method for determining the mean size of single-crystal nanoparticlesor crystallites in nanocrystalline bulk materials. The rst scientist to investigate the eect of limited particle size on X-ray diraction patterns was Paul Scherrer, who published his results in a paper that included what became known as the Scherrer equation1. However, it seems tous that this equation is oen erroneously referred to as the DebyeScherrer equation. (Indeed, strictly speaking, there is no Debye-Scherrer equation.) We would, therefore, like to recall some relevant historical facts to illuminate the origins of the Scherrer equation, and to assist authors in citing the appropriate equations and references in future work.
Between 1915and 1917 Scherrer andhis PhD supervisor, Peter Debye, worked together at the University of Gttingen to develop methods2,3 for analysing crystal structures using samples of ne powder. Their motivation was to avoid the problem of growing the large single crystals that were needed to use the methods developed by Max von Laue and the Braggs (William Henry and his son William Lawrence),and to facilitate the cumbersome data evaluation processes associated withthese methods3. Their method, which was independently developed around the same time by Albert...