Determination of the incommensurately modulated structure ofα-uranium below 37 K

The modulated structure of {α}-uranium is analyzed with use of the neutron scattering data of Marmeggi et al. [Solid State Commun. 43, 577 (1982)]. The results of the refinements are given for all the superspace groups compatible with the neutron diffraction pattern. Fits to the experimental data of equal quality are obtained for different structure models (different symmetries), thus prohibiting the determination of the structure from neutron scattering alone. Together with the recently reported results of electron microscopy, the refinements lead to a unique assignment of a superspace group to the incommensurately modulated structure of {α}-uranium below T=37 K, with the tentative symbol P2/m11(1/2{β}{γ}). The values of the structural parameters, as follow from the refinements, are also reported.