Diffraktionsdata

Diffraktionsdata, also spelled Diffraktionsdaten in German, are measurements that describe how waves scatter from a material. They arise in X-ray, electron, and neutron diffraction experiments and record how the scattered intensity varies with angle or with reciprocal-space coordinates. Typical data include intensity I as a function of 2θ or q, plus experimental metadata such as wavelength and temperature.

In crystallography and materials science, diffraktionsdata are used to determine crystal structures, lattice parameters, and phase composition. A key derived quantity is the structure factor F(hkl) or its amplitude |F(hkl)|, which relates to the arrangement of atoms in the unit cell. Data quality depends on instrument geometry, sample quality, and corrections for effects like absorption.

Processing of such data involves background subtraction, Lorentz and polarization corrections, and absorption corrections, followed by indexing, peak fitting, and refinement. Common approaches include Rietveld and Le Bail refinements, which adjust structural parameters to reproduce the observed pattern and yield reliability indicators such as R-factors.

Diffraktionsdaten are stored in standardized formats and shown in public databases. Formats include CIF, XRDML, and instrument-specific files, with metadata on wavelength, temperature, pressure, and geometry. Repositories such as the Crystallography Open Database host large collections of diffraction data for minerals, compounds, and biomolecules.

Applications span chemistry, geology, materials science, and biology. They enable phase identification, quantitative phase analysis, determination of microstructure, and texture assessment. Software tools for data reduction and refinement include GSAS, FullProf, TOPAS, and various instrument vendors, all within established reporting standards to ensure reproducibility.