$xray diffraction pair distribution function$

The Power of X-Ray Diffraction Pair Distribution Function: Unlocking Structural Insights in Disordered Materials

Pair distribution function (PDF) analysis, enabled by x-ray diffraction (XRD) and neutron diffraction (ND) measurements, has revolutionized the field of materials science by providing a powerful tool to probe the structure of disordered materials. These materials lack long-range order and periodicity, making it challenging to determine their structural properties using conventional methods.

By applying XRD and ND techniques, researchers can extract g(r), the pair distribution function (PDF), which represents the probability of finding two atoms at a given distance from each other. The PDF is obtained by expressing it as a linear sum of error functions whose parameters are refined through a nonlinear least square fit method.

In this approach, both Bragg scattering and underlying diffuse scattering are determined, allowing researchers to gain insights into the structural properties of disordered materials. For instance, our recent study has shown that water restructuring occurs at the vapor/water interface. This discovery was made possible by analyzing the total scattering or pair distribution function (PDF) using the complete powder XRD pattern.

Performing measurements below the critical angle for total reflectivity enables researchers to obtain the structure factor of the topmost layers of the water/vapor interface. By applying corrections to scans at different incident beam angles above the critical angle, the measured intensities can be collapsed into a single master curve without any fitting parameters, yielding S(q), the structure factor.

The corrections used to obtain S(q) are self-consistent and have been described in detail. Interestingly, our study has demonstrated that the structure factor of water can be obtained from x-ray synchrotron experiments at grazing angle of incidence using a liquid surface diffractometer.

To further validate this approach, we conducted PDF analyses using conventional laboratory X-ray powder diffraction (XRPD) instrumentation and compared them to those obtained using high-energy X-rays. Our results show that both techniques yield similar insights into the structural properties of disordered materials.

$xray diffraction pair distribution function$

In conclusion, the x-ray diffraction pair distribution function is a powerful tool for unlocking structural insights in disordered materials. By applying this approach, researchers can gain a deeper understanding of the behavior of these materials and make significant strides in advancing our knowledge of their properties and applications.

$xray diffraction pair distribution function$

Xray diffraction pair distribution function