GSAS software

All samples were single phase without detectable impurities. The crystal structure was refined by the Rietveld method (Rietveld, 1959) from X-ray powder diffraction data using GSAS software package (Larson Von Dreele, 1994). 

A number of software programs are known for stmcture refinement. The most common programs used are FUULPROF, GSAS, RIETAN, and TOPAS. ... 

C.A. Larsen and R.B. Von Dreele, GSAS General structure analysis system. LANL, Los Alamos, New Mexico, USA (2000). The cited user manual and software are freely available via FTP at ftp //ftp.lanl.gov/public/gsas/. 

There is a variety of freely available software, which enables one to deconvolute a powder diffraction pattern and determine either or all individual intensities, lattice and peak shape function parameters, and observed structure factors of all possible Bragg reflections. Freeware codes include EXPO, FullProf, GSAS, LHPM-Rietica, and others. In addition to free programs, nearly all manufacturers of commercial powder diffractometers offer software for sale either as a package with the sale of the equipment or as stand-alone products. ... 

Just as in the case of full pattern decomposition, we will use two freely available software codes (LHPM-Rietica and GSAS ) to carry out Rietveld refinements using either or both x-ray and neutron diffraction data. Many... 

Some software products, e.g. GSAS, require specification of the population parameters as g, while the multiplicities of site positions are automatically included by the program. 

These two relationships can be easily programmed in GSAS and in the majority of Rietveld software codes by using a constraint apparatus, which was briefly discussed above (see section 7.3.3 and Eq. 7.9). Since the constraints affect only the shifts that are determined during every least squares refinement cycle but not the values of the related parameters, the latter should be synchronized manually prior to imposing constraints. For example, in our case when the computed shift for g-v2a is 0.02, then the new values of the constrained parameters (Eqs. 7.9, 7.11 and 7.12) will be calculated as follows ... 

Care must be taken, as many file formats are ill-defined and where software does not convert some file formats into the described specifications. An example of the later is that of file converters which convert GSAS STD format files without including the STD flag in the second header line (line 2). 

Pawley Software. Due to early limitations on computing powder, and relative difficulty of implementation in existing Rietveld software, a less common fitting option is that of Pawley fitting. Pawley fitting is now available in the GSAS Rietveld software (Table 17.17). 

Compression tests are carried out as per ASTM Cl65 and ASTM D1621 using the Instron 5569 Universal Testing Machine as shown in Fig. 5.3. Each GSA and GSA-SDS sample was cut into a square specimen of x y dimensions of 17.5 2.5 width 27.5 1.5 mm height (in z-direction) using razor blades. The blocks were compression tested in the z-direction at three strain rates, viz, 0.8/min, 1.2/min at the nominal strain up to 44.4 %, and at 1.0/min. Each specimen was loaded in compression using 500 N 4 % load cell with the initial load of 25 % of the nominal strain for 1 min and, thereafter was unloaded. The compressive modulus for each specimen is calculated with the in-built Instron Bluehill software. 

Software package such as General Structure alysis stem (GSAS) (7, 9) and Rietica 10) are based on Rietveld methods and allow one to analyze the entire diffraction pattern at once instead of analyzing each diffraction peak individually. Essentially, the Rietveld method enables the user to create a... 

Analysis software Qualitative analysis Quantitative analysis Diffrac.Suite Eva, HighScore Topas (Academic), HighScore (Plus),GSAS, FullProf... 

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