Disordered Material Structure Using Advanced Pair Distribution Function Methods
Pair distribution function (PDF) measurements are becoming increasingly routine for structural studies of disordered, complex, and nano-crystalline materials. However I am primarily interested in extending these methods to enable us to gain more structural insight into amorphous and complex crystalline materials. In this talk I will introduce some of the key science motivations for studying the structure of amorphous materials, and will discuss a few directions in which I have been pushing these PDF methods, with examples of the new science that was enabled.
This includes accurate x-ray structure factor measurements of liquid water to high-Q (momentum transfer). This required development of measurement and correction procedures, which enabled the first precise determination of the height and width of the oxygen-oxygen distribution in liquid water. Partial structure factor determination of high temperature (>2000C) oxide liquids, which involves isotopic/isomorphic substitution, x-ray scattering, neutron scattering, and high temperature sample environments.Third the floating water bridge, which is the formation of a rope-shaped connection of liquid water between two beakers under a high electric field. Analysis of this involved extension of scattering theory to measure and simulate anisotropic-amorphous pair distribution function patterns. Finally I will give a couple ideas for future directions.