Structural, Photoluminescence and Electron Density Distribution Analysis of Rutile Phase TiO2

In this work, the mixed anatase and rutile phases of commercial TiO2 sample was purchased and converted to single rutile phase by sintering at 1000°C. Structural and spectroscopic analysis of the single phased rutile TiO2 were analyzed by PXRD, SEM, EDS, PL analysis, respectively. Rietveld profile refinement technique was performed to fit the observed and calculated PXRD profiles. Charge density distribution studies were used to determine the chemical bonding nature of Ti-O bond by maximum entropy method (MEM). From the MEM calculations, Ti-O bond exhibited covalent nature. PL measurements showed that the emission wavelength of rutile TiO2 at around 470 nm which may be due to band to band transitions of Ti and O atoms.

Structural and Charge Density Properties of Manganese Sulfide

Single phased Manganese Sulfide was analyzed by powder X-ray diffraction (PXRD) data sets with cubic structure. The simulated XRD data sets were used to analyze the structure of manganese sulfide. The powder profile refinements were done by Rietveld profile refinement technique. The refinement results were subjected to analyze the charge density analysis using structure factors. The chemical bonding nature between Mn and S were analyzed by charge density distribution studies through maximum entropy method. From MEM analsysis, it found that the bonding between Mn and S atoms is ionic in nature.

Structural and Bonding Behavior Analysis of Microwave Sintered ZnO:Co materials

In this present study, Zn1-xCoxO (x = 0.0, 0.04 & 0.06) samples were synthesized using conventional solid state sintering process and characterized by PXRD and SEM. The structural analysis was done using Rietveld profile refinement technique. The chemical bonding features and nature between Zn and O atoms was analyzed by charge distribution studies. The bonding between Zn and O is clearly visible in the three- dimensional and two-dimensional MEM maps. One- dimensional charge density distribution analysis clearly reveals that the characteristics of the bond. MEM results were also correlated with the PXRD parameters.

Structural and Photocatalytic Analysis of Niwo4 Materials

The different pH levels of NiWO4 materials were synthesized by co-precipitation route. The insight unit cell properties were studied by Powder X-ray diffraction (PXRD). The detailed structural analyses were done by Rietveld profile refinement method. The morphology on the surface of the synthesized NiWO4 materials was evaluated by scanning electron microscopic images. The presence of elements in the prepared materials were confirmed by energy dispersive X-ray spectroscopy (EDS) analysis. The photocatalytic activities of prepared materials are performed on methylene blue which is degraded by irradiation of catalyst in 50 minutes under ultra violet light.

The development of powder profile refinement at the Reactor Centre Netherlands at Petten

With thousands of references to `Rietveld refinement' it is forgotten that the method did not suddenly appear in a flash of inspiration of a single person, but was the result of the work of three individuals working in the 1960s at the Reactor Centre Netherlands at Petten, Loopstra, van Laar and Rietveld. This paper outlines the origins of `profile refinement', as it was called at Petten, and also looks at why it took so long for the scientific community to recognize its importance. With the recent passing of Hugo Rietveld, the death of Bert Loopstra in 1998 and before other pioneers also disappear, it is important to set down a first-hand account.

Rietveld Refinement Strategy of CaTa4-xNbxO11 Solid Solutions Using GSAS-EXPGUI Software Package

Crystal structures of CaTa4-xNbxO11 solid solutions (x = 0, 1 and 2) in space group P6322, have been refined by application of the Rietveld method X-ray powder diffraction profile. Refinement were carried out using GSAS software and EXPGUI interface. The unit cell parameters and cell volume increase with increasing Nb content; all samples contain random distribution of Ta/Nb. Strategy and procedures for CaTa4-xNbxO11 solid solutions refinement are reported. The structure consists of layers of tantalum-oxygen bipyramids sharing-edges alternating with layers of octahedra.

Synthesis and crystal structure refinement of new perovskite oxides, Dy0.55Sr0.45Mn1−xFexO3 (x = 0.0 and 0.2) from X-ray powder diffraction data

Polycrystalline compounds of Dy0.55Sr0.45Mn1−xFexO3 (x = 0.0 and 0.20) were synthesized using ceramic method and characterized by X-ray powder diffraction technique using CuKα (1.5406 Å) radiation at room temperature. All the diffraction peaks were indexed to an orthorhombic cell with space group Pnma (#62). Whole powder diffraction profile refinement was performed using GSAS package.

TEMPERATURE DEPENDENT DIELECTRIC BEHAVIOR OF NANOCRYSTALLINE Ca FERRITE

Dielectric behaviour of Nanocrystalline CaFe2O4 ferrite synthesized by advanced sol- gel method has been investigated as a function of frequency at different temperatures. Rietveld profile refinement of the XRD pattern confirms formation of cubic spinel structure of the specimen.The dispersion in dielectric behavior of CaFe2O4 ferrite sample has been observed in the temperature range of 100-250˚C as a function of frequency in the range 75 kHz to 10 MHz Both the real value of dielectric constant (ɛ′) and the dielectric loss factor (tanδ) decrease with frequency. This decrease in the values of ɛ′ and tanδ could be explained on the basis of available ferrous, i.e. Fe2+ , ions on octahedral sites such that beyond a certain frequency of applied electric field the electronic exchange between the ferrous and ferric ions i.e. Fe2+↔Fe3+ cannot follow the applied alternating electric field.

“Powder 3D Parametric”- A program for Automated Sequential and Parametric Rietveld Refinement Using Topas

A new program to perform fast sequential and parametric whole powder profile refinement of in situ time-resolved powder diffraction data is presented. The program interacts with the launch mode kernel of the total powder pattern analysis software suite Topas® for doing the refinements. The program provides a graphical interface platform, upon which the huge Topas input command files necessary to perform sequential and parametric refinements can be easily prepared and executed. This program requires the user license dongle for Topas academic version 3 or higher.