Alasdair R Preston

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The electronic structure of single-crystal WO3 and Na0.67WO3 (a sodium-tungsten bronze) has been measured using soft x-ray absorption and resonant soft x-ray emission oxygen K-edge spectroscopies. The spectral features show clear differences in energy and intensity between WO3 and Na0.67WO3. The x-ray emission spectrum of metallic Na0.67WO3 terminates in a(More)
The electronic structure of NdVO(3) and YVO(3) has been investigated as a function of sample temperature using resonant inelastic soft x-ray scattering at the V L(3)-edge. Most of the observed spectral features are in good agreement with an atomic crystal-field multiplet model. However, a low energy feature is observed at ∼ 0.4 eV that cannot be explained(More)
Soft x-ray emission and absorption spectroscopy of the O K-edge are employed to investigate the electronic structure of wurtzite ZnO͑0001͒. A quasiparticle band structure calculated within the GW approximation agrees well with the data, most notably with the energetic location of the Zn 3d –O 2p hybridized state and the anisotropy of the absorption spectra.(More)
1-D STRAFI (STRAy FIeld) imaging is used to study water distribution in a sandy loam. The matric potential of the soil can be varied during acquisition of 1-D profiles. Results at a range of potentials are presented showing both the equilibrium distribution and the evolution of the profile following an abrupt change in matric potential. The air breakthrough(More)
Development, characterization, and preliminary results of a recent technique capable of local measurements of pore-size distribution by a spatially resolved low resolution nuclear magnetic resonance (NMR) technique are described. Potential environmental uses include studying the change in pore-size distribution caused by surface compaction, which influences(More)
This paper explains how the convergent beam electron diffraction (CBED) and large angle convergent beam (LACBED) techniques can be used to study crystal defects, bicrystals, and multilayers. It is shown how the LACBED technique in particular can be used to derive the magnitude and sign of the Burgers vectors of dislocations and displacements at stacking(More)
The element and orbital-specific electronic structure of thin films of the organic material N,N'-ethylene-bis(1,1,1-trifluoropentane-2,4-dioneiminato)-copper(II) (designated as Cu-TFAC) has been studied using a combination of synchrotron radiation-excited resonant X-ray emission spectroscopy, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy(More)
A stray field (STRAFI) module has been added to the GAMMA magnetic resonance simulation platform in order to facilitate computational investigations of NMR experiments in large static field gradients that are on the order of 50 T/m. The package has been used to examine system response during echo trains generated by the application of shaped pulses. The(More)
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