EXPGUI Tutorial: Garnet (part 5)

5. Plot data using POWPLOT or LIVEPLOT

At this point in the GSAS tutorial in the manual, program POWPLOT is used to plot the diffraction data. This is done by pressing POWPLOT button in the button bar, or by pressing the POWPLOT menu item in either the Powder menu or the Graphs menu. The input supplied to POWPLOT and the results are the same as what is shown in the menu, so this will not be shown.

EXPGUI does offer another way to display diffraction data, LIVEPLOT. Similar to the way POWPREF was run in the previous step, LIVEPLOT can be started by pressing LIVEPLOT button in the button bar, or by pressing the LIVEPLOT menu item in the Graphs menu.

Since two cycles of refinement have been run, LIVEPLOT generates a plot similar to the one above, showing the observed data (black X's), simulated (computed) data (red line), the fitted background (green line) and the difference between the observed and computed data (lower black line),

Note that the region shown in the plot can be changed by clicking with the left mouse button to outline a region, as shown above. When the left mouse button is pressed a second time, the graph is "zoomed in," as is shown below. To "zoom out" to the previous region, press the right mouse button.

Reflection positions can be marked, using the File/Tickmarks menu. Likewise, reflection indices can be displayed by pressing the "h" (or "H") key in the position of the reflection to be labeled. The size and time before the reflection labels are removed is determined by values in the Options/HKL labeling menu.

There are many other options available in LIVEPLOT in the Options menu. The Appearance and location of the tickmarks can be set, for example, using the "Options/Configure Tickmarks/Auto locate option causes the tickmarks to be shown as small lines under each reflection. The symbol and symbol size used for observed data can be selected. The X and Y units can be changed to Q or d-space values. Background can be subtracted. The legend can be removed from the plot.

Previous step: Run POWPREF and GENLES
Next step: Additional Least-Squares Refinement

Comments, corrections or questions: crystal@NIST.gov

$Revision: 597 $ $Date: 2009-12-04 23:08:50 +0000 (Fri, 04 Dec 2009) $