Probing atomic displacements with thermal differential EXAFS

Differential extended X-ray absorption fine structure (DiffEXAFS) is a novel technique for the study of small atomic strains. Here the development of this technique to the measurement of thermally induced strain is presented. Thermal DiffEXAFS measurements have been performed on α-Fe and SrF₂, yielding α = (11.6 ± 0.4) × 10⁻⁶ K⁻¹ and (19 ± 2) × 10⁻⁶ K⁻¹, respectively. These are in good agreement with accepted values, proving the viability of the technique. Analysis has revealed sensitivity to mean atomic displacements of 0.3 fm.