Multiple scattering in grazing-incidence X-ray diffraction: impact on lattice-constant determination in thin films

This study reveals comparable intensities of the split peaks with a maximum for incidence angles close to the critical angle of total external reflection of the substrate. This observation is rationalized by two different scattering pathways resulting in diffraction peaks at different positions at the detector. In order to minimize the splitting, the data suggest either using incident angles well below the critical angle of total reflection or angles well above, which sufficiently attenuates the contributions from the second scattering path. This study highlights that the refraction of X-rays in (organic) thin films has to be corrected accordingly to allow for the determination of peak positions with sufficient accuracy. Based thereon, a reliable determination of the lattice constants becomes feasible, which is required for crystallographic structure solutions from thin films.
Source: Journal of Synchrotron Radiation - Category: Physics Authors: Tags: organic thin films X-ray scattering grazing-incidence diffraction surface reflection X-ray refraction grazing-incidence X-ray diffraction refraction correction research papers Source Type: research
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