Bragg-Brentano method

Two common geometries are used for collecting powder diffraction data, either the reflection or Bragg-Brentano method (Figure 8.29a) which uses a flat plate sample holder made either of glass or, ideally, of an... 

We show by X-ray diffraction in the Bragg-Brentano geometry that the atomic stmcture of lead sulfide nanoparticles in thin films prepared by wet chemical method is different from the B stmcture, which is the equilibrium phase for bulk single-crystalline PbS. The atomic structure of nanoparticles can be desaibed by the cubic space group Fm-3m with both tetrahedral and octahedral coordinations for sulfur atoms. 

There are no limitations on the size of the source, sample or receiving slit, and correspondingly on the axial or equatorial divergence. The proposed method, valid over a full range of 26 from 0 to 180°, can be applied to different diffractometer geometries. We shall restrict our consideration here to the common Bragg Brentano geometry. 

By means of X-ray Bragg-Brentano diffraction experiment and ab initio calculation of powder diffraction intensity using Debye equation it is shown that the atomic structure of cadmium sulfide (CdS) nanoparticles prepared by the wet chemical method is disordered. They have a closed packed atomic structure with the tetrahedral coordination for both elements, cadmium and sulfur, but with a non-periodical sequence of the closed-packed planes A, B, and C. 

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