Search results for "Electron diffraction"
showing 10 items of 191 documents
The crystallisation of copper(ii) phenylphosphonates
2016
The crystal structures and syntheses of four different copper(II) phenylphosphonates, the monophenylphosphonates α-, β-, and γ-Cu(O3PC6H5)·H2O (α-CuPhPmH (1) β-CuPhPmH (2) and γ-CuPhPmH (3)), and the diphosphonate Cu(HO3PC6H5)2·H2O (CuPhP2mH (4)), are presented. The compounds were synthesized from solution at room temperature, at elevated temperature, under hydrothermal conditions, and mechanochemical conditions. The structures of α-CuPhPmH (1) and CuPhP2mH (4) were solved from powder X-ray diffraction data. The structure of β-CuPhPmH (2) was solved by single crystal X-ray analysis. The structures were validated by extended X-ray absorption fine structure (EXAFS) and DTA analyses. Disorder …
A high pressure gas target system for the determination of absolute electron scattering cross sections
1979
A high pressure gas target system is described, which is suitable for measurements of absolute electron scattering cross sections and for high resolution electron scattering experiments at medium energies. Details of design and construction are given and special investigations are discussed with respect to straggling effects that take place in the walls and in the gases, and to changes in the gas density, due to heating by the electron beam.
The Elusive Structure of Magadiite, Solved by 3D Electron Diffraction and Model Building
2021
In addition to a great swelling ability, layered silicates also allow the functionalization of their interlayer region to form various robust green materials that are used as CO2 adsorbents, drug c...
Structural Relationships between Floating and Deposited Monolayers of Docosanoic Acid
1991
Floating docosanoic acid (behenic acid) monolayers in the SmI and SmH phase were deposited with the Langmuir-Blodgett technique onto thin polymethylmethacrylate (PMMA) and Formvar substrates and investigated by electron diffraction. The molecular packing of the monolayers on the substrates vary from those on the water surface and are different for different substrates. On PMMA four phases (H, SmB, SmI, SmL) have been identified, depending on the deposition conditions. While SmB and SmI are known for docosanoic acid on the water surface, H and SmL have only been unequivocally observed in other substances or on other subphases. The monolayer structure on Formvar was identical under all deposi…
Synthesis of a New Copper-Azobenzene Dicarboxylate Framework in the Form of Hierarchical Bulk Solids and Thin Films without and with Patterning
2011
Reaction of copper(II) acetate with azobenzene-4,4′-dicarboxylic acid results in the formation of a metal–organic framework with the unexpected stoichiometry of Cu(II):ligand of 2:1. The bulk synthesis results in microspheres assembled from either nanobricks or nanoflakes, depending on the ratio of the reactants in solution. While the former behaves like a bulk solid with clear reflections in the X-ray and electron diffraction experiments, the latter obviously is dominated by surface effects, with a significant fraction of slightly expanded elemental cells and a significantly increased outer surface area. The material could also be deposited on a variety of surfaces using a stepwise layer-b…
High-Pressure Synthesis of Novel Boron Oxynitride B6N4O3 with Sphalerite Type Structure
2015
A novel crystalline boron oxynitride (BON) phase has been synthesized under static pressures exceeding 15 GPa and temperatures above 1900 °C, from molar mixtures of B2O3 and h-BN. The structure and composition of the synthesized product were studied using high-resolution transmission electron microscopy, electron diffraction, automated diffraction tomography, energy dispersive X-ray spectroscopy and electron energy-loss spectroscopy (EELS). BON shows a hexagonal cell (R3m, Z = 3) with lattice parameters a = 2.55(5) A and c = 6.37(13) A, and a crystal structure closely related to the cubic sphalerite type. The EELS quantification yielded 42 at % B, 35 at % N, and 23 at % O (B:N:O ≈ 6:4:3). E…
Femtosecond four-wave-mixing spectroscopy of suspended individual semiconducting single-walled carbon nanotubes.
2010
Femtosecond four-wave-mixing (FWM) experiments of individual suspended semiconducting single-walled carbon nanotubes (SWCNTs) are presented. The chiral indices of the tubes were determined by electron diffraction as (28,14) and (24,14) having diameters of 2.90 and 2.61 nm, respectively. The diameter and semiconducting character of the tubes were additionally confirmed by resonance Raman measurements. The FWM signal showed electronic response from the SWCNTs. The results demonstrate that ultrafast dynamics of individual SWCNTs can be studied by FWM spectroscopies.
Layer-by-Layer Graphene Growth on β-SiC/Si(001)
2019
ACS nano 13(1), 526 - 535 (2019). doi:10.1021/acsnano.8b07237
Evidence of hexagonal WO3 structure stabilization on mica substrate
2009
International audience; WO3 nanorods are grown by a simple vapor deposition method on a mica substrate and characterized by Selected Area Electron Diffraction and Energy Dispersive X-rays Spectroscopy. Experimental results show the clear evidence of an unexpected WO3 hexagonal structure as well as an epitaxial growth on the mica substrate. Besides, potassium is evidenced inside the nanorods. It is thus deduced that a metastable WO3 hexagonal phase is stabilized by epitaxy through a tungsten bronze interlayer having same hexagonal structure.
Differences and Similarities between the Isotypic AntimonidesMFe1−xSb, ScCo1−xSb, andMNiSb (M=Zr, Hf)
1999
The new antimonides MFe{sub 1{minus}x}Sb can be synthesized by arc-melting of M, Fe, and MSb{sub 2} (M = Zr, Hf). All title compounds crystallize in the TiNiSi structure type (space group Pnma, Z = 4). The lattice parameters of the new phases of MFe{sub 1{minus}x}Sb, as obtained from the bulk samples of the nominal compositions MFeSb, are a = 681.4(1) pm, b = 417.87(7) pm, c = 740.3(1) pm for ZrFe{sub 1{minus}x}Sb and a = 674.0(1) pm, b = 412.0(2) pm, c = 729.7(2) pm for HfFe{sub 1{minus}x}Sb. Under the reaction conditions used, the occupancy factors of the iron position content of ZrFe{sub 1{minus}x}Sb does not exceed 68(1)% (i.e., x = 0.32(1)). Extended Hueckel calculations, performed on …