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Abstract: High-temperature polyol methods were used to fabricate micro- or nano-sized gold plates. 1,2-propanediol served as both medium and reducing agent. Triangular plates and polygonal plate shapes derived from triangular prisms as well as pentagonal structured gold particles have been synthesized. Poly(vinylpyrrolidone) (PVP) plays an important role, but is not necessary, for the formation of these structures. These gold plates may have applications in the characterisation of adsorbed proteins or peptides

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Abstract: The local structure of the Au(111)(?3×?3)R30° -methylthiolate surface phase has been investigated by S?K -edge near-edge s-ray absorption fine structure(NEXAFS) both experimentally and theoretically and by experimental normal-incidence x-ray standing waves (NIXSW) at both the C and S atomic sites. NEXAFS shows not only excitation into the intramolecular ? ? S–C resonance but also into a ? ? S–Au orbital perpendicular to the surface, clearly identifying the local S headgroup site as atop a Au atom. Simulations show that it is not possible, however, to distinguish between the two possible adatom reconstruction models; a single thiolate species atop a hollow-site Au adatom or a dithiolate moiety comprising two thiolate species bonded to a bridge-bonded Au adatom. Within this dithiolate moiety a second ? ? S–Au orbital that lies near parallel to the surface has a higher energy that overlaps that of the ? ? S–C resonance. The new NIXSW data show the S–C bond to be tilted by 61° relative to the surface normal, with a preferred azimuthal orientation in ?211? , corresponding to the intermolecular nearest-neighbor directions. This azimuthal orientation is consistent with the thiolate being atop a hollow-site Au adatom, but not consistent with the originally proposed Au-adatom-dithiolate moiety. However, internal conformational changes within this species could, perhaps, render this model also consistent with the experimental data.

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Abstract: The effect of prolonged contact time (up to 130 days) on the immobilization of Cd by sorption to calcium exchanged zeolite-X (CaX), under environmentally relevant conditions, was studied using both isotopic exchange and extended X-ray absorption fine structure spectroscopy (EXAFS). Sorption and isotopic exchange measurements revealed time-dependent Cd sorption and indicated the movement of Cd2+ ions into less accessible sites due to ageing. EXAFS suggested progressive fixation of Cd in the double six-ring (D6R) unit of the CaX structure. Proportional allocation of the apparent Cd–Si bond distance to two ‘end-members’, across all contact times, indicated that the bond distance for labile Cd was 3.41 Å and for non-labile (or fixed) Cd was 3.47 Å.

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Abstract: Using x-ray magnetic dichroism, we characterize the magnetic order in La 0.7 Sr 0.3 MnO 3 (LSMO)/La 0.7 Sr 0.3 FeO 3 (LSFO) superlattices with six unit cell thick sublayers. The LSMO layers exhibit a reduced Curie temperature compared to the bulk while antiferromagnetic order in the LSFO layers persists up to the bulk Néel temperature. Moreover, we find that aligning the LSMO magnetization by a magnetic field within the (001) surface plane leads to a reorientation of the Fe moments as well maintaining a perpendicular orientation of Fe and Mn moments. This perpendicular alignment is due to the frustrated exchange coupling at the LSMO/LSFO interface.

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Abstract: The solvation structure of yttrium (III) in dimethyl sulfoxide has been determined by studying both the extended X-ray absorption fine structure (EXAFS) and the X-ray absorption near edge structure (XANES) regions of the Y K-edge absorption spectra. Although the EXAFS technique provides accurate information about the next neighbors coordination distances, no unambiguous determination of the coordination polyhedron is obtained. This failure is counteracted by the study of the near-edge part of the absorption spectrum (XANES) because of its high sensitivity to the bonding geometry. We have performed an extensive and systematic ab initio computation of the Y K-edge XANES spectrum of yttrium (III) in dimethyl sulfoxide within the multiple-scattering framework. The comparison between the experimental data and the theoretical calculations has demonstrated that the solvation sphere of the yttrium cation is best modeled by eight dimethyl sulfoxide molecules each oriented to give an Y−O−S angle close to 130°.