The newly developed GSAS-II software is a general purpose package for data reduction, structure solution and refinement that can be used with both single-crystal powder diffraction from neutron X-ray sources, including laboratory synchrotron collected on two- one-dimensional detectors. It intended will eventually replace the GSAS EXPGUI packages, as well many other utilities. open source written largely in object-oriented Python but offers speeds comparable to compiled code because of its...

A set of general guidelines for structure refinement using the Rietveld (whole-profile) method has been formulated by International Union Crystallography Commission on Powder Diffraction. The practical rather than theoretical aspects each step in a typical are discussed with view to guiding newcomers field. focus is X-ray powder diffraction data collected laboratory instrument, but features specific from neutron (both constant-wavelength and time-of-flight) synchrotron radiation sources also...

The mathematical functions necessary for Rietveld refinement of time-of-flight neutron powder diffraction patterns from spallation sources are developed and a computer program least-squares analysis is described. results refinements nickel low-carbon steel described discussed. method fully exploits the high resolution (Δd/d ~ 0.3 0.5%) available with diffractometers currently in operation on these examples given precise determination atom coordinates, thermal parameters, lattice parameters...

A generalized spherical-harmonic description of the texture for polycrystalline materials has been implemented in a multiple-phase/multiple-data-set Rietveld refinement code. It tested using two sets neutron time-of-flight data taken from standard calcite sample previously used round-robin study [Wenk (1991). J. Appl. Cryst. 24 , 920–927] and shown to give similar results as those obtained individual pole figures. Simultaneous crystal structure including anisotropic thermal parameters gives...

A new dedicated high-resolution high-throughput powder diffraction beamline has been built, fully commissioned, and opened to general users at the Advanced Photon Source. The optical design commissioning results are presented. Beamline performance was examined using a mixture of NIST Si Al(2)O(3) standard reference materials, as well LaB6 line-shape standard. Instrumental resolution high 1.7 x 10(-4) (DeltaQQ) observed.

A dedicated high-resolution high-throughput X-ray powder diffraction beamline has been constructed at the Advanced Photon Source (APS). In order to achieve goals of both high resolution and throughput in a instrument, multi-analyzer detector system is required. The design performance 12-analyzer installed on diffractometer 11-BM APS are presented.

Lithium-ion batteries are essential for portable technology and now poised to disrupt a century of combustion-based transportation. The electrification revolution could eliminate our reliance on fossil fuels enable clean energy future; advanced would facilitate this transition. However, owing the demanding performance, cost, safety requirements, it is challenging translate new materials from laboratory prototypes industrial-scale products. This Perspective describes that journey lithium-ion...

Macrostrain variations in engineering components are frequently examined using neutron diffraction, at both reactors and pulsed sources. It is desirable to minimize the sampling volume order maximize spatial resolution, although this increases required measurement time. At reactors, macrostrain behavior inferred from a single lattice reflection (deemed be representative of bulk response). source, complete diffraction pattern recorded accordingly it natural fit entire spectra Rietveld [J....

The whole-pattern least-squares fitting method (herein called the pattern-fitting structure-refinement, PFSR, method) developed by Rietveld and used many with neutron powder data has been extended for use X-ray diffractometer data. Examples of PFSR specimens in five different space groups are given. Structural parameters generally agree, within 2σ, those from single-crystal results where available. Atom positions site occupancies were determined LaPO4 Ca5PO4)3F, quartz. R(pattern) values...

MgTiO 3 cristallise dans R3 avec affinement jusqu'a 0,0257. Mg 2 TiO 4 Fd3m ou P4 1 22 apres recuit a 973 K 773 K. MgTi O 5 Bbmm et possede une structure pseudobrookite

Abstract TiNb 2 O 7 represents a promising anode material for lithium‐ion batteries (LIBs), but its practical applications are currently hampered by the non‐negligible volumetric expansion and contraction during charge/discharge process sluggish ion/electron kinetics. A combination technique is reported systematically optimizing porous spherical morphology, crystal structure, surface decoration of mesoporous Cu 2+ ‐doped microspheres to enhance electrochemical Li + storage performance...

In this paper we describe the capabilities for texture measurements of new neutron time-of-flight diffractometer HIPPO at Los Alamos Neutron Science Center. The orientation distribution function (ODF) is extracted from multiple histograms using full-pattern analysis first described by Rietveld. Both, well-established description ODF spherical harmonics functions and WIMV method, more recently introduced data, are available to routinely derive data. At ambient conditions, total count time...

Rietveld refinements using neutron powder diffraction data were used to locate H atom positions and obtain a more precise crystal structure refinement for akaganéite [Fe3+7.6Ni2+0.4O6.35 (OH)9.65Cl1.25·nH2O]. Difference Fourier maps clearly showed atoms near those O at the midpoints of tunnel edges. The O-H vectors point toward Cl sites center tunnel, weak hydrogen bonds likely form between framework Cl. position is prism defined by eight hydroxyl atoms. fill ~2/3 sites, suggesting an...

When multiple elastic diffraction peaks are obtained from an x-ray or neutron source, data analysis is commonly performed using a Rietveld refinement applied to the entire pattern, rather than simply performing single peak fits. In simplest case crystal structure assumed be ideal despite presence of stresses which, coupled with and plastic anisotropy individual grains, can result in nonisotropic response polycrystal. A first step account for this include anisotropic strain parameter. earlier...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSilver trifluoride: preparation, crystal structure, some properties, and comparison with AuF3Boris Zemva, Karel Lutar, Adolf Jesih, William J. Casteel Jr., Angus P. Wilkinson, David E. Cox, Robert B. Von Dreele, Horst Borrmann, Neil BartlettCite this: Am. Chem. Soc. 1991, 113, 11, 4192–4198Publication Date (Print):May 1, 1991Publication History Published online1 May 2002Published inissue 1...

X-ray and neutron powder diffraction data for superconducting orthorhombic ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathrm{x}}$ have been used in a joint refinement to give room-temperature structure which includes very precise set of atom positions thermal-motion parameters. Broadening the peaks indicates that these materials are highly strained, contrary number suggestions literature, no evidence is found any cation disorder.

Atomic positions in geological aragonite and biogenic aragonite, obtained from several mollusk shells, were precisely measured by high-resolution neutron diffraction, which is more sensitive than X-ray diffraction to the of light atoms, C O, CaCO3 structure. Comparable analysis atomic revealed, for first time, changes some bond lengths configurations specimens with respect ones. Most pronounced are modifications aplanarity carbonate groups. These correlate observed shifts ν2 frequency IR...

We used high-resolution neutron powder diffraction to accurately measure the atomic positions and bond lengths in biogenic geological calcite. A special procedure for data analysis was developed order take into account considerable amounts of magnesium present all investigated samples. As a result, calcite we found some bonds have significantly different as compared those calcite, after contribution is accounted for. The maximum effect (elongation up 0.7%) C−O bonds. also analyzed changes...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAntineoplastic agents. 46. The isolation and structure of dolatriolGeorge R. Pettit, Richard H. Ode, Cherry L. Herald, Robert B. Von Dreele, Claude MichelCite this: J. Am. Chem. Soc. 1976, 98, 15, 4677–4678Publication Date (Print):July 1, 1976Publication History Published online1 May 2002Published inissue 1 July 1976https://doi.org/10.1021/ja00431a072Request reuse permissionsArticle Views226Altmetric-Citations72LEARN ABOUT THESE METRICSArticle...