Pair-Distribution Functions Pair-distribution function (PDF) measurements were performed at the 11-ID-B beamline at the Advanced Photon Source at Argonne National Laboratory. High-energy synchrotron XRD (λ = 0.2128 Å) 2D total scattering data was collected and integrated into one-dimensional diffraction data using FIT2D . The PDFgetX3 software was used to carry out Fourier transformation and correction of the PDFs . Refinements were performed using the software PDFgui .