Search results for "Diffraction tomography"

showing 10 items of 32 documents

Fast-ADT: A fast and automated electron diffraction tomography setup for structure determination and refinement.

2020

Abstract Electron crystallography has focused in the last few years on the analyses of microcrystals, mainly organic compounds, triggered by recent publications on acquisition methods based on direct detection cameras and continuous stage tilting. However, the main capability of a transmission electron microscope is the access to features at the nanometre scale. In this context, a new acquisition method, called fast and automated diffraction tomography (Fast-ADT), has been developed in form of a general application in order to get the most of the diffraction space from a TEM. It consists of two subsequent tilt scans of the goniometric stage; one to obtain a crystal tracking file and a secon…

010302 applied physicsDiffractionMaterials scienceMicroscopeElectron crystallographybusiness.industryContext (language use)02 engineering and technology021001 nanoscience & nanotechnology01 natural sciencesAtomic and Molecular Physics and OpticsElectronic Optical and Magnetic Materialslaw.inventionDiffraction tomographyOpticsElectron diffractionlawGoniometer0103 physical sciences0210 nano-technologybusinessInstrumentationPowder diffractionUltramicroscopy
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Automated Diffraction Tomography for the Structure Elucidation of Twinned, Sub-micrometer Crystals of a Highly Porous, Catalytically Active Bismuth M…

2012

010405 organic chemistryChemistrystructure elucidationInorganic chemistrychemistry.chemical_elementGeneral Medicine02 engineering and technologyGeneral Chemistry010402 general chemistry021001 nanoscience & nanotechnologyHeterogeneous catalysis01 natural sciencesCatalysis0104 chemical sciencesBismuthbismuth; heterogeneous catalysis; metal-organic frameworks; structure elucidationSub micrometerDiffraction tomographyheterogeneous catalysisChemical engineeringbismuthHighly porousMetal-organic framework0210 nano-technologymetal-organic frameworksAngewandte Chemie International Edition
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Essential features of the polytypic charoite-96 structure compared to charoite-90

2011

AbstractCharoite, ideally (K,Sr,Ba,Mn)15–16(Ca,Na)32[(Si70(O,OH)180)](OH,F)4·nH20, is a rock-forming mineral from the Murun massif in Yakutia, Sakha Republic, Siberia, Russia, where it occurs in a unique alkaline intrusion. Charoite occurs as four different polytypes, which are commonly intergrown in nanocrystallme fibres. We report the structure of charoite-96(a =32.11(6),b =19.77(4),c =7.23(1) Å, β = 95.85(9)°,V =4565(24) Å3, space groupP21/m),which was solvedab initioby direct methods on the basis of 2676 unique electron diffraction reflections collected by automated diffraction tomography and refined toR1/wR2=0.34/0.37. The structure of charoite-96 is related to that of the charoite-90,…

010504 meteorology & atmospheric sciencesElectron crystallographyAb initiocrystal structure analysisengineering.material010502 geochemistry & geophysicscharoite polytypes01 natural sciencesSilicateNanocrystalline materialchemistry.chemical_compoundCrystallographyelectron crystallographychemistryOctahedronElectron diffractionGeochemistry and PetrologyGroup (periodic table)Charoitecharoite polytypes; crystal structure analysis; electron crystallography; electron diffraction; electron diffraction tomographyengineeringelectron diffractionelectron diffraction tomography0105 earth and related environmental sciences
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The Bi sulfates from the Alfenza Mine, Crodo, Italy: An automatic electron diffraction tomography (ADT) study

2014

We report about three bismuth sulfates from mineralized quartz dikes from Alfenza (Crodo, Italy), two new phases and a rare mineral, cannonite, all growing on bismuthinite. The first new phase occurs as white, "hortensia-like" aggregates of pseudo-hexagonal platelets, with perfect basal cleavage, similar to 20 mu m wide and few micrometers thick. The approximate composition is Bi2O2(SO4), and cell parameters and symmetry, as determined by automatic diffraction tomography, are a = 22.0(4), b = 16.7(3), c = 15.9(3) angstrom, beta = 102.9(5)degrees, space group Pc or P2/c. A major stacking disorder is detected by HR-SEM images and electron diffraction data.The second new phase was detected onl…

AcicularMaterials scienceElectron crystallography automatic diffraction tomography bismuth sulfate cannonite porous phaseElectron crystallographyElectron crystallography; automatic diffraction tomography; bismuth sulfate; cannonite; porous phaseElectron crystallographychemistry.chemical_elementautomatic diffraction tomographyengineering.materialGEO/06 - MINERALOGIABismuthbismuth sulfateBismuthiniteDiffraction tomographyCrystallographyGeophysicschemistryElectron diffractionGeochemistry and PetrologyPhase (matter)engineeringcannoniteQuartzElectron crystallography; bismuth sulfate; cannonite; automatic diffraction tomographyporous phase
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MZ-35, a new layered pentasil borosilicate synthesized in the presence of large alkali cations

2013

Abstract A new layered borosilicate has been synthesized in the presence of cesium and sodium cations and its structure has been solved by a combination of automated diffraction tomography (ADT) and X-ray powder diffraction (XRPD). MZ-35 has a composition NaCs 2 [BSi 7 O 16 (OH) 2 ](OH) 2 ·4H 2 O and features space group P-4m2. The unusually small unit cell ( a 7.3081 A, c 10.7520 A) is shared by two random-stacked configurations of the structure: a network of connected pentasil units related to the layer of RUB-18 and a bidimensional checkerboard of intersecting ladders of 4-membered rings. The two configurations are related by the simple face-sharing inversion of a hydroxyl-bearing tetrah…

Automated electron diffraction tomography; Rietveld structure refinement; Layered borosilicate; 4-MR ladders; Face-sharing terahedraMaterials science4-MR laddersSodiumchemistry.chemical_element02 engineering and technology010402 general chemistry01 natural sciencesDiffraction tomographyFace-sharing terahedraGroup (periodic table)General Materials ScienceRietveld structure refinementLayered borosilicateBorosilicate glassAutomated electron diffraction tomographyGeneral Chemistry4-MR ladders; Automated electron diffraction tomography; Face-sharing terahedra; Layered borosilicate; Rietveld structure refinement[CHIM.MATE]Chemical Sciences/Material chemistry021001 nanoscience & nanotechnologyCondensed Matter PhysicsAlkali metal4-MR ladders; Automated electron diffraction tomography; Face-sharing terahedra; Layered borosilicate; Rietveld structure refinement;0104 chemical sciencesCrystallographychemistryMechanics of MaterialsCaesiumTetrahedron0210 nano-technologyPowder diffraction
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The structure of charoite, (K,Sr,Ba,Mn)(15-16)(Ca,Na)(32)[(Si-70(O,OH)(180))](OH,F)(4.0)center dot nH(2)O, solved by conventional and automated elect…

2010

AbstractCharoite, ideally (K,Sr,Ba,Mn)15–16(Ca,Na)32[(Si70(O,OH)180)](OH,F)4.0·nH2O, a rare mineral from the Murun massif in Yakutiya, Russia, was studied using high-resolution transmission electron microscopy, selected-area electron diffraction, X-ray spectroscopy, precession electron diffraction and the newly developed technique of automated electron-diffraction tomography. The structure of charoite (a= 31.96(6) Å,b= 19.64(4) Å,c= 7.09(1) Å, β = 90.0(1)°,V= 4450(24) Å3, space groupP21/m) was solvedab initioby direct methods from 2878 unique observed reflections and refined toR1/wR2= 0.17/0.21. The structure can be visualized as being composed of three different dreier silicate chains: a d…

Charoite010504 meteorology & atmospheric sciencesChemistryAb initioPrecession electron diffraction (PED)engineering.material010502 geochemistry & geophysics01 natural sciencesCrystal structure analysisCrystalAutomated electron diffraction tomography (ADT)CrystallographyElectron diffractionOctahedronGeochemistry and PetrologyCharoiteengineeringAutomated electron diffraction tomography (ADT); Charoite; Crystal structure analysis; Precession electron diffraction (PED)Precession electron diffractionMoleculeSpectroscopy0105 earth and related environmental sciences
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Atomic structure solution of the complex quasicrystal approximant Al77Rh15Ru8 from electron diffraction data

2014

The crystal structure of the novel Al77Rh15Ru8phase (which is an approximant of decagonal quasicrystals) was determined using modern direct methods (MDM) applied to automated electron diffraction tomography (ADT) data. The Al77Rh15Ru8E-phase is orthorhombic [Pbma,a= 23.40 (5),b= 16.20 (4) andc= 20.00 (5) Å] and has one of the most complicated intermetallic structures solved solely by electron diffraction methods. Its structural model consists of 78 unique atomic positions in the unit cell (19 Rh/Ru and 59 Al). Precession electron diffraction (PED) patterns and high-resolution electron microscopy (HRTEM) images were used for the validation of the proposed atomic model. The structure of the E…

ChemistryMetals and AlloysQuasicrystalCrystal structureelectron diffraction tomography; icosahedral and decagonal quasicrystals; modern direct methodsAtomic and Molecular Physics and OpticsElectronic Optical and Magnetic MaterialsCrystallographyElectron diffractionmodern direct methodsMaterials ChemistryAtomic modelicosahedral and decagonal quasicrystalsPrecession electron diffractionOrthorhombic crystal systemelectron diffraction tomographyHigh-resolution transmission electron microscopyElectron backscatter diffraction
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Automated Diffraction Tomography: A New Era for Electron Crystallography

2011

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

Diffraction tomographyCrystallographyMaterials scienceElectron crystallographyInstrumentationMicroscopy and Microanalysis
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Advances in automated diffraction tomography

2009

Crystal structure solution by means of electron diffraction or investigation of special structural features needs high quality data acquisition followed by data processing which delivers cell parameters, space group and in the end a 3D data set. The final step is the structure analysis itself including structure solution and subsequent refinement.

Diffraction tomographyData setData processingMaterials scienceElectron diffractionbusiness.industryData qualityTomographyCrystal structurebusinessAutomationComputational science
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Automated Electron Diffraction Tomography

2012

Ab-initio structure analysis by electron diffraction is hampered by two major problems: insufficient number of reflections sampled and an intensity alteration by dynamical scattering contribution or beam damage. Thus, in recent years the principles of automated diffraction tomography (ADT) allowing systematic reciprocal space sampling and automated data analysis were developed. Here the basic ideas of ADT and its general applicability will be discussed along with some examples of solved structures.

Diffraction tomographyReciprocal latticeSampling (signal processing)Electron diffractionElectron crystallographyScatteringEwald's sphereTomographyComputational physics
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