Suchergebnisse

At high pressures, autoionization - along with polymerization and metallization - is one of the responses of simple molecular systems to a rise in electron density. Nitrosonium nitrate (NO+NO3-), known for this property, has attracted a large interest in recent decades and was reported to be synthesized at high pressure and high temperature from a variety of nitrogen-oxygen precursors, such as N2O4, N2O and N-2-O-2 mixtures. However, its structure has not been determined unambiguously. Here, we present the first structure solution and refinement for nitrosonium nitrate on the basis of single-crystal X-ray diffraction at 7.0 and 37.0 GPa. The structure model (P2(1)/m space group) contains the triple-bonded NO+ cation and the NO3- sp(2)-trigonal planar anion. Remarkably, crystal-chemical considerations and accompanying density-functional-theory calculations show that the oxygen atom of the NO+ unit is positively charged - a rare occurrence when in the presence of a less-electronegative element. ; Funding Agencies|Alexander von Humboldt FoundationAlexander von Humboldt Foundation; Federal Ministry of Education and Research, Germany (BMBF)Federal Ministry of Education & Research (BMBF) [05K19WC1]; Deutsche Forschungsgemeinschaft (DFG)German Research Foundation (DFG) [DU 954-11/1, DU 393-9/2, DU 393-13/1]; DFGGerman Research Foundation (DFG)European Commission [DFG FOR2125, WI1232]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]

Abstract
The temperature dependence of unit cell parameters was studied using high-temperature X-ray diffraction and the coefficient of thermal expansion of SnSe single crystal was determined. Fluorescence spectra of SnSe single crystal grown by the Bridgman-Stockbarger method were examined using a Cary Eclipse spectrophotometer at room temperature in the wavelength range 200–900 nm. When the samples were irradiated by a pulse at a wavelength of 230 nm, the fluorescence spectra exhibited maxima at wavelengths 313.07, 423.03, 458.93, 495.07, and 530.00 nm.

"Union Carbide Corporation Nuclear Division operating the Oak Ridge Gaseous Diffusion Plant, Oak Ridge Y-12 Plant, Oak Ridge National Laboratory, and Paducah Gaseous Diffusion Plant for the Atomic Energy Commission under U.S. government contract W-7405-eng-26." ; "Date Issued: June 19, 1964" ; "April 24, 1964" ; Y-1470-E ; "Chemistry; TID-4500 (29th Edition)." ; Includes bibliographical references (p. 11). ; U.S. Atomic Energy Commission ; Mode of access: Internet.

"Union Carbide Corporation Nuclear Division operating the Oak Ridge Gaseous Diffusion Plant, Oak Ridge Y-12 Plant, Oak Ridge National Laboratory, and Paducah Gaseous Diffusion Plant for the Atomic Energy Commission under U.S. government contract W-7405-eng-26." ; "Date Issued: May 29, 1964" ; "April 24, 1964" ; Y-1470-B ; "Chemistry; TID-4500 (29th Edition)." ; Includes bibliographical references (p. 11). ; U.S. Atomic Energy Commission ; Mode of access: Internet.

"Union Carbide Corporation Nuclear Division operating the Oak Ridge Gaseous Diffusion Plant, Oak Ridge Y-12 Plant, Oak Ridge National Laboratory, and Paducah Gaseous Diffusion Plant for the Atomic Energy Commission under U.S. government contract W-7405-eng-26." ; "Date Issued: June 26, 1964" ; "April 24, 1964" ; Y-1470-F ; "Chemistry; TId-4500 (29th Edition)." ; Includes bibliographical references (p. 11). ; U.S. Atomic Energy Commission ; Mode of access: Internet.

"Union Carbide Corporation Nuclear Division operating the Oak Ridge Gaseous Diffusion Plant, Oak Ridge Y-12 Plant, Oak Ridge National Laboratory, and Paducah Gaseous Diffusion Plant for the Atomic Energy Commission under U.S. government contract W-7405-eng-26." ; "Date Issued: April 24, 1964" ; "July 3, 1964" ; Y-1470-G ; "Chemistry; TID-4500 (29th Edition)." ; Includes bibliographical references (p. 11). ; U.S. Atomic Energy Commission ; Mode of access: Internet.

"Union Carbide Corporation Nuclear Division operating the Oak Ridge Gaseous Diffusion Plant, Oak Ridge Y-12 Plant, Oak Ridge National Laboratory, and Paducah Gaseous Diffusion Plant for the Atomic Energy Commission under U.S. government contract W-7405-eng-26." ; "Date Issued: September 29, 1964" ; "August 17, 1964" ; Y-1470-I ; "Chemistry; TID-4500 (32nd Edition)." ; Includes bibliographical references (p. 11). ; U.S. Atomic Energy Commission ; Mode of access: Internet.

"Union Carbide Corporation Nuclear Division operating the Oak Ridge Gaseous Diffusion Plant, Oak Ridge Y-12 Plant, Oak Ridge National Laboratory, and Paducah Gaseous Diffusion Plant for the Atomic Energy Commission under U.S. government contract W-7405-eng-26." ; "Date Issued: June 5, 1964" ; "April 24, 1964" ; Y-1470-C ; "Chemistry; TID-4500 (29th Edition)." ; Includes bibliographical references (p. 11). ; U.S. Atomic Energy Commission ; Mode of access: Internet.

Mixed crystals Cs1−x(NH4)xH2PO4 of the ferroelectric CsH2PO4 (CDP) and the antiferroelectric (NH4)H2PO4 were grown with x=0.2 (CADP0.2) in solution. The structural properties of the crystal were analyzed by means of x-ray diffraction. Dielectric measurements at several temperatures and frequencies have been performed along the three crystallographic axes in this sample and also in the fully deuterated CADP0.2 sample (DCADP0.2). NMR experiments were also performed. ; NSFgrantDMR-9520215; Basque Government under grant BFI96.041

A combination of X-ray tomography and electron backscatter diffraction (EBSD) was applied to investigate both the shape of voids and the plastic deformation around voids in an Al single crystal shock-loaded in the direction. The combination of these two techniques allows the addition of crystallographic information to X-ray tomography and allows the addition of three-dimensional information to EBSD data. It is found that the voids are octahedral with {1 1 1} faces and that regular patterns of lattice reorientation exist around individual voids. The results provide new insights to the process of void growth during shock loading, which is important for both civil and military applications.

Conka, Tuba/0000-0003-0671-3805 ; WOS:000402701600027 ; PubMed: 28656042 ; The full strain and stress tensor determination in a triaxially stressed single crystal using X-ray diffraction requires a series of lattice spacing measurements at different crystal orientations. This can be achieved using a tunable X-ray source. This article reports on a novel experimental procedure for single-shot full strain tensor determination using polychromatic synchrotron radiation with an energy range from 5 to 23 keV. Microbeam X-ray Laue diffraction patterns were collected from a copper micro-bending beam along the central axis (centroid of the cross section). Taking advantage of a two-dimensional energy-dispersive X-ray detector (pnCCD), the position and energy of the collected Laue spots were measured for multiple positions on the sample, allowing the measurement of variations in the local microstructure. At the same time, both the deviatoric and hydrostatic components of the elastic strain and stress tensors were calculated. ; BMBF VerbundforschungFederal Ministry of Education & Research (BMBF) [05K13PS1]; knock-on initiative of the School of Science and Engineering of Siegen University; Austrian Federal Government ; This work was supported by BMBF Verbundforschung, project No. 05K13PS1, and by the knock-on initiative of the School of Science and Engineering of Siegen University. JK appreciates the financial support of the Austrian Federal Government within the research activities of the K2 Competence operated by the Materials Center Leoben Forschungs GmbH in the framework of the Austrian COMET Competence Centre Programme.