In this paper we describe the capabilities for texture measurements of the new neutron time-offlight diffractometer HIPPO at the Los Alamos Neutron Science Center (LANSCE). The orientation distribution function (ODF) is extracted from multiple neutron time-of-flight histograms using the full-pattern analysis first described by Rietveld. Both, the well-established description of the ODF using sp...

The outcome of the ab-initio crystal structure solution process by Direct Methods depends on not only the quality of the extracted integrated intensities but also the experimental resolution [1]. In fact, the limited experimental resolution distorts the Fourier synthesis even at atomic resolution: when the resolution is larger than 1 Å, the electron density map is an imperfect representation of...

— The structure of [Co(NH3)5CO3]NO3•H2O is determined ab initio from conventional X-ray powder diffractometry by the direct methods. The cell is monoclinic, space group P21, Z = 2, a = 7.6733(4) Å, b = 9.6398(5) Å, c = 7.0852(3) Å and β = 106.195(3)°. Refinements by the Rietveld method, lead to RB = 0.053, RP = 0.100, and RWP = 0.119. Hydrogen atoms could not be located. Nevertheless a bonding ...

In this work, LiCoPO4 nanoparticles were synthesized by supercritical fluid method using cobalt nitrate hexahydrate (Co(NO3)2 6H2O) and cobalt acetate tetrahydrate (C4H6CoO4 4H2O) as starting materials. The effect of starting materials on particle morphology, size, and the crystalline phase were investigated. The as-synthesized samples were systematically characterized by XRD, TEM, STEM, EDS, B...

The title compound, C16H12N2, was investigated in a powder diffraction study and its structure refined utilizing the Rietveld Method. The mol-ecule has approximate C2 symmetry. The dihedral angle between the rings is 25.6 (7)°. The crystal packing is consolidated by weak C-H⋯C N hydrogen-bond-like contacts, which lead to the formation of a three-dimensional network. Further stabilization of the...

Powderous crystalline materials of the composition Fe3−xMnxC have been prepared by first synthesizing Fe3C via mechanical alloying in a planetary mill followed by the addition of elemental manganese and arc-plasma melting or via the classic ceramic route in an electric furnace. The milling time for the synthesis of Fe3C was significantly reduced through adjusting the parameters of the planetary...

The analysis of observed structure factors estimated after Rietveld analysis by the maximum-entropy method (MEM) gives electron or nuclear densities in the unit cell. The resultant densities are, more or less, biased toward a structural model in the Rietveld analysis. To overcome such a problem, we devised a sophisticated technique named MEM-based pattern fitting (MPF). For this purpose, a patt...

The structure refinement of X-ray powder data using the Rietveld method often results in false minima, i.e. not necessarily the energetically favored result. By introducing force fields as a new type of constraint into the recently developed BGMN program, a fully featured X-ray Rietveld system was created. With the model of bonding and nonbonding interactions, it was finally possible to refine ...