Gregorkiewitz Miguel, Boschetti Alice
Department of Physical, Earth and Environmental Sciences, University of Siena, Italy.
Acta Crystallogr A Found Adv. 2024 Nov 1;80(Pt 6):439-445. doi: 10.1107/S2053273324008799. Epub 2024 Oct 3.
In powder diffraction, lattice symmetry relaxation causes a peak to split into several components which are not resolved if the degree of desymmetrization is small (pseudosymmetry). Here the equations which rule peak splitting are elaborated for the six minimal symmetry transitions, showing that the resulting split peaks are generally broader and asymmetric, and suffer an hkl-dependent displacement with respect to the high-symmetry parent peak. These results will be of help in Rietveld refinement of pseudosymmetric structures where an exact interpretation of peak deformation is required.
在粉末衍射中，晶格对称性弛豫会导致一个峰分裂成几个成分，如果去对称化程度较小（赝对称性），这些成分无法分辨。这里针对六种最小对称性转变详细阐述了控制峰分裂的方程，结果表明，产生的分裂峰通常更宽且不对称，并且相对于高对称母峰存在与晶面指数（hkl）相关的位移。这些结果将有助于对需要精确解释峰形变的赝对称结构进行里特韦尔德精修。
