Buy article online - an online subscription or single-article purchase is required to access this article.
research papers
Integrated X-ray Bragg intensities from Nb single crystals have been measured as a function of H concentration and scattering vector along high-symmetry directions. The observed attenuation can be described in terms of a static Debye–Waller factor (DWF) due to the static displacements of the Nb lattice atoms around the dissolved H. The crystals were loaded with H in situ on the X-ray diffractometer. The static DWF was determined from the ratio of the intensities from a crystal with and without H. Corrections are necessary for several magnitudes which change with the lattice-parameter change and the change of the thermal displacements upon the uptake of H. The measured static DWF is proportional to the H concentration c(H/Nb) for c≤0.30 and the square of the scattering vector K2 for small K, as expected from theory. From analysis of the static DWF the static displacements of the Nb atoms closest to the H impurity u1 = 0.1 Å were determined.