Combining density functional theory (DFT) and pair distribution function (PDF) analysis to solve the structure of metastable materials: the case of metakaolin
Claire E White, John L Provis, Thomas Proffen, Daniel P Riley, Jannie SJ van Deventer
PHYSICAL CHEMISTRY CHEMICAL PHYSICS | ROYAL SOC CHEMISTRY | Published : 2010
Understanding the atomic structure of complex metastable (including glassy) materials is of great importance in research and industry, however, such materials resist solution by most standard techniques. Here, a novel technique combining thermodynamics and local structure is presented to solve the structure of the metastable aluminosilicate material metakaolin (calcined kaolinite) without the use of chemical constraints. The structure is elucidated by iterating between least-squares real-space refinement using neutron pair distribution function data, and geometry optimisation using density functional modelling. The resulting structural representation is both energetically feasible and in exc..View full abstract
Awarded by DOE
This work was funded in part by the Australian Research Council (ARC) (including some funding via the Particulate Fluids Processing Centre, a Special Research Centre of the ARC), and in part by a studentship paid to Claire White by the Centre for Sustainable Resource Processing via the Geopolymer Alliance. The density functional modelling work was supported by an award under the Merit Allocation Scheme on the NCI National Facility at the ANU. Travel funding for the experimental work conducted at Los Alamos National Laboratory was provided through the ANSTO Access to Major Research Facilities Program. We thank Dr Hyunjeong Kim (LANL) for assistance on the NPDF beamline, Prof. Don Kearley (ANSTO) for useful discussions regarding density functional modelling, and Dr Kia Wallwork (Australian Synchrotron) for assistance in collecting the X-ray powder diffraction data. The PDF work was carried out on NPDF at the Lujan Center at Los Alamos Neutron Science Center, funded by DOE Offce of Basic Energy Sciences. Los Alamos National Laboratory is operated by Los Alamos National Security LLC under DOE Contract DE-AC52-06NA25396. The upgrade of NPDF has been funded by the NSF through grant DMR 00-76488. X-Ray diffraction data were collected on the Powder Diffraction beamline (10BM1) at the Australian Synchrotron, Victoria, Australia. The views expressed herein are those of the authors and are not necessarily those of the owner or operator of the Australian Synchrotron.