A description and justification of the EXPGUI program is presented. This implements a graphical user interface shell for GSAS single-crystal Rietveld package. Use Tcl/Tk scripting language allows to be platform independent. Also included synopsis how implemented.

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...

The definitions for important Rietveld error indices are defined and discussed. It is shown that while smaller index values indicate a better fit of model to the data, wrong models with poor quality data may exhibit than some superb very high data.

Multiferroic behavior in perovskite-related metal−organic frameworks of general formula [(CH3)2NH2]M(HCOO)3, where M = Mn, Fe, Co, and Ni, is reported. All four compounds exhibit paraelectric−antiferroelectric phase transition the temperature range 160−185 K (Mn: 185 K, Fe: 160 K; Co: 165 Ni: 180 K); this associated with an order−disorder involving hydrogen bonded dimethylammonium cations. On further cooling, become canted weak ferromagnets below 40 K. This research opens up a new class...

The results of both a line-broadening study on ceria sample and size–strain round robin diffraction methods, which was sponsored by the Commission Powder Diffraction International Union Crystallography, are presented. prepared heating hydrated at 923 K for 45 h. Another to correct effects instrumental broadening annealing commercially obtained 1573 3 h slowly cooling it in furnace. measurements were carried out with two laboratory synchrotron X-ray sources, constant-wavelength neutron...

[(CH3)2NH2]Zn(HCOO)3, 1, adopts a structure that is analogous to of traditional perovskite, ABX3, with A = [(CH3)2NH2], B Zn, and X HCOO. The hydrogen atoms the dimethyl ammonium cation, which bond oxygen formate framework, are disordered at room temperature. X-ray powder diffraction, dielectric constant, specific heat data show 1 undergoes an order-disorder phase transition on cooling below 156 K. We present evidence this classical paraelectric antiferroelectric driven by ordering atoms....

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.

Structural analysis from powder neutron and single-crystal x-ray diffraction data for a sample of the Tl 2 Mn O 7 pyrochlore, which exhibits colossal magnetoresistance (CMR), shows no deviations ideal stoichiometry. This gives an Mn-O distance 1.90 angstroms, is significantly shorter than distances (1.94 to 2.00 angstroms) observed in phases based on LaMnO 3 perovskites that exhibit CMR. Both results indicate oxidation states very close 3+ 4+ . Thus, has neither mixed valence double-exchange...

Pair distribution function (PDF) analysis of neutron or X-ray powder diffraction data is a useful technique for short-range structure in both amorphous and crystalline materials. Errors PDF determinations may arise from several sources: termination the Fourier transform, lack instrument resolution, counting statistics inaccurate corrections experimental artifacts. Estimates amount error resolution are computed using model structure. A general method estimating expected contribution...

The high dielectric constant in "SrCu3Ti4O12" and the giant CaCu3Ti4O12 are based on a barrier layer mechanism. Conductivity conducting regions is related to Ti Cu sites. insulating barriers between crystallites but within CaCu3Ti4O12.

Deviations in atomic positions from those of the average crystallographic structure superconducting ${\mathrm{Tl}}_{2}$${\mathrm{ba}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{8}$ were studied by pair-distribution function (PDF) analysis pulsed-neutron-scattering data. The PDF shows a clear change local at onset superconductivity. In addition to previously observed displacements Tl and O within Tl-O sheets, correlated Cu perpendicular Cu-O plane have been found. arrangement atoms appears be...

Abstract The structures of M 1 and 2 in MoVNbTeO propane ammoxidation catalysts have been solved using a combination TEM, neutron powder diffraction, synchrotron X-ray diffraction. unit cell is Pba (No. 32) with = 21.134(2) Å, b 26.658(2) c 4.0146(3) Å Z 4. formula Mo 7.8 V 1.2 NbTe 0.937 O 28.9 . Pmm 25) 12.6294(6) 7.29156(30) 4.02010(7) 4.31 1.36 Te 1.81 Nb 0.33 19.81 Tellurium sites hexagonal channels both phases are displaced toward vanadium-occupied framework sites, whereas the...

Synchrotron high-resolution powder X-ray diffraction (HRPXRD) data and Rietveld structure refinements were used to examine the crystal structures of quartz, sodalite, tremolite, meionite Me79.6, compare them with those obtained by single-crystal (SXTL). The purpose is illustrate that HRPXRD are comparable SXTL. comparisons indicate important significant differences between two methods. cell parameters using appear superior quality distances in pure SiO4 tetrahedron tremolite 1.6081(3),...

The determination by powder neutron diffraction of the ambient temperature crystal structures compounds in NaxCoO2 family, for 0.3 < x <= 1.0, is reported. consist triangular CoO2 layers with Na ions distributed intervening charge reservoir layers. shapes CoO6 octahedra that make up are found to be critically dependent on electron count and distribution layers, where two types sites available. Correlation cobalt-oxygen octahedra, ion positions, electronic phase diagram made, showing how...

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...

The crystal structure of Na0.5CoO2, determined by powder neutron diffraction, is reported. consists layers edge-shared CoO6 octahedra in a triangular lattice, with Na ions occupying ordered positions the interleaving planes. form one-dimensional zigzag chains. Two types Co ions, which differ only subtly their coordination oxygen, are also found Specific heat measurements show that transitions observed at 87 K and 53 resistivity magnetic susceptibility accompanied changes entropy. Electron...

The atomic positional correlations in superconducting ${\mathrm{Tl}}_{2}$${\mathrm{Ba}}_{2}$Ca${\mathrm{Cu}}_{2}$${\mathrm{O}}_{8}$ were studied by pair-distribution-function analysis of the pulsed-neutron scattering data. results show for first time strongly correlated local displacements both thallium and oxygen atoms Tl-O plane from high-symmetry crystallographic sites. As a consequence Tl form chains or pairs accompanied displacement nearby atoms, resulting locally orthorhombic order....

Precursor-mediated molecular chemisorption and thermal desorption are examined by means of a lattice-gas model using combination time-dependent Monte Carlo simulations deterministic rate equations. Lateral interactions between coadsorbates assumed to be both pairwise additive limited in range nearest next-nearest neighbors. The interrelationships among kinetics, energetics, adsorbate overlayer structures analyzed detail. method is applied the interaction nitrogen with Ru(001) surface.

The crystal structure of dehydrated Cs5.8Al5.8Si90.2O192 has been determined by Rietveld refinement synchrotron powder diffraction data. was refined in the Pnma space group to Rwp = 2.52% and R(F2) 5.32%. Cs ions were found with partial occupancy three different positions. One these, Cs1, is channel intersection, near sinusoidal 10-ring system adjacent a four-membered ring. second, Cs2, straight 10-ring. third, Cs3, 3.18 Å from Cs1 also area. total 5.32(3) ions, which compares well unit cell...