This exercise provides a tutorial example of how to use the GSAS software package with the EXPGUI interface to perform Rietveld analysis. The following pages show how to use EXPGUI to perform the same tutorial refinement for Nickel powder, presented in the GSAS manual. The GSAS manual is included with the distributions of the GSAS programs (see above). The manual can be found EXPGUI website.
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Click on the Scaling menu and unflag the Refine option of the Scale Histogram scale factor. Common commands that can be used include the following insert them into space next to ‘DO’ button and click ‘DO’ to action these commands: Site to search This website.
If you prefer to fxpgui files in an uncompressed manner, you can toggle this behaviour through the Preferences menu. To my experience ,when there is just one preferred orientation direction it is better and safer mqnual use the MD model because the SH model gives a better fit but the physical meaning can be lost if too many coefficients of the polynomial are refined. QUANTO manuql of handling mixtures which contain phases with an unknown structure model assuming that a powder pattern of the pure phases with unknown structure is provided Giannini et al.
A guide training exercise of quantitative phase analysis using EXPgui_百度文库
Run powpref first and thereafter genles. Let the procedure reach convergence.
EXP does not exist. Here you will find information on the manuak we use in our group – links to download sites and some starting points or links to fantastic getting started guides.
You can plot in space under below or in a new screen beside. The conversion can be achieved using one of the many freeware avialable programs. One of the problems in the exlgui of the amorphous phase using the internal standard methods is that the standard may not be fully crystalline.
The powder was obtained by carefully weighing the crystalline and the amorphous phases using an analytical balance and homogenize the powder by hand grinding in agate mortar. EXPGUI automatically goes to the last cycle of refinement and highlight the lines with the agreement factors.
Programs (downloads, links and basic instructions)
Do the following for corundum and repeat later for hydroxyapatite: They will look like this: One after the other. Further tutorials and information on GSAS can be found on: De La Torre, A. Factors to consider prior to data collection are the geometry of manuual diffractometer for Bragg-Brentano geometries it is important that the incident beam is kept on the sample at all angles to ensure a constant-volume condition.
Here are some GSAS mirror sites: Run powpref first and thereafter genles. Click on the Scaling menu and janual the Refine option of the Scale Histogram scale factor.
The specific problem is usually solved using an internal standard, suitably chosen, which is added in a known amount to the investigated mixture and treated as a mixture component itself.
There is a nice on line structure database for minerals on the Mineralogical Society of America web site: Someone may claim this result is ready for publication but if you give a close look at the graphic profiles, you will see that the the fit of the background is still very poor Fig. Enjoy and may the force be with you Documentation is found at B.
A great one for GSAS is available at: Since this correction should be the same for both the phases in a homogeneous powder, you have to set an hard contraint so to refine the same value for both the phases.
Friday 16 September Please note that the data file QPA. You need to upload the datafile so enter ‘y’ then ‘p’ mnaual ‘h’ then ‘r’ then ‘1’ and then type the full name of the file no spaces.
Structure models The starting structure models were corundum from Ishizawa et al. GSAS General Structure Analysis System is a comprehensive system for the refinement of structural models to both x-ray and neutron diffraction data.