source: trunk/tutorial1/nickel6.html @ 493

Last change on this file since 493 was 209, checked in by toby, 12 years ago

# on 2000/06/09 03:57:42, toby did:
incorporate many useful comments by Egbert Keller

  • Property rcs:author set to toby
  • Property rcs:date set to 2000/06/09 03:57:42
  • Property rcs:lines set to +41 -7
  • Property rcs:rev set to 1.3
  • Property rcs:state set to Exp
  • Property svn:keywords set to Author Date Revision Id
File size: 4.6 KB
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1<html>
2<head>
3   <META NAME="Author" CONTENT="Brian H. Toby">
4   <title>EXPGUI Tutorial #6</title>
5</head>
6<BODY BGCOLOR="#FFFFFF">
7
8<A HREF=http://www.ncnr.nist.gov>
9<IMG SRC="http://www.ncnr.nist.gov/images/ncnrtrans.gif" 
10alt="Link to NIST Center for Neutron Research home page"
11ALIGN=RIGHT></A>
12<A HREF=http://www.nist.gov>
13<IMG SRC="http://www.ncnr.nist.gov/images/webidblue_2lineright.gif" 
14alt="Link to National Institute of Standards & Technology home page"
15ALIGN=LEFT></A>
16<CENTER>
17<A Href="http://www.ncnr.nist.gov/programs/crystallography/software/tclpkgs.html">
18<IMG SRC="tcltklogo100.gif" 
19alt="Link to Tcl/Tk information">
20</CENTER></A>
21<hr>
22
23<CENTER>
24<H1>GSAS Nickel example using EXPGUI (part 6)</H1>
25</CENTER>
26<H1>
276. Plot data using POWPLOT or LIVEPLOT
28</H1>
29At this point in the GSAS tutorial
30program POWPLOT is used to plot the diffraction data. This
31is done in EXPGUI by pressing POWPLOT button in the button bar, or
32by pressing the POWPLOT menu item in either the Powder menu
33or the Graphs menu. The input supplied to POWPLOT and the
34results are the same as what is shown in the menu, so this will
35not be repeated here.
36<P>
37EXPGUI does offer another way to display diffraction data, LIVEPLOT.
38Similar to the way POWPREF was run in the previous step,
39LIVEPLOT can be started by pressing LIVEPLOT button in the button bar,
40or by pressing the LIVEPLOT menu item in the Graphs menu.
41<P>
42<img src="liveplot1.gif" align=left>
43Since no cycles of refinement have been run,
44after LIVEPLOT has generated a blank window, it must be
45triggered to read the POWPREF output by pressing the "Update Plot"
46item in the File menu.
47A plot similar to the one to the left is then displayed.
48<P>
49The contents of the LIVEPLOT window are discussed more fully
50<A HREF="#liveplot">
51below</A>, but
52note that the calculated diffraction intensities are all
53zero at this point, since GENLES
54has not yet been to run to simulate the pattern.
55Likewise the background values have not yet been fit so
56this curve is a poor fit.
57The blue line shows the values of
58obs-calc (diff), offset negatively. The sum of the fixed background
59values plus the fitted background function is shown
60difference
61pattern is
62<BR clear=left><P>
63<img src="liveplot2.gif" align=left>
64Note that the region plotted can be changed by clicking with the left
65mouse button, to outline the region to be shown, as seen to the left.
66When the left mouse button is pressed a second time, the graph is "zoomed in,"
67as is shown below.
68To "zoom out" to the previous region, press the right mouse button.
69<BR clear=left><P>
70<img src="liveplot3.gif">
71<P>
72<img src="liveplot4.gif" align=left>
73Reflection positions can be marked, using the File/Tickmarks menu.
74<BR clear=left><P>
75<img src="liveplot5.gif" align=left>
76Reflection indices can be displayed by pressing the "h" (or "H") key in the
77position of the reflection to be labeled. The size and time before
78the reflection labels are removed is determined by values in the Options/HKL labeling menu.
79<BR clear=left><P>
80<I>Do not exit LIVEPLOT at this time as it will be used again in part 8 of this
81tutorial.</I>
82<a name="liveplot">
83<H4>LIVEPLOT Contents and Options</H1>
84</a>
85Note that the observed data points (obs) are marked with "x" symbols in
86LIVEPLOT.
87This can be changed in the Options/Obs symbol menu. The simulated
88diffraction data based on the crystallographic model (calc) is shown as
89a red line. The lower blue line shows the values of
90obs-calc (diff), offset negatively to avoid overlapping with the previous
91curves. The green line (mostly obscured in this figure) shows the background
92function (bckg). This is the sum of the fixed background
93values (if any) plus the fitted background function (if used).
94The dashed magenta vertical lines denote reflection positions. The color
95and lengths of these lines can be customized using the
96options/Configure Tickmarks menu item, for example, auto placement mode
97creates the more customary short tickmarks placed below the pattern,
98at different heights when more than one phase is present.
99<P>
100There are many other options available in LIVEPLOT in the Options menu. The
101Appearance and location of the tickmarks can be set. The symbol and symbol size
102used for observed data can be selected.
103The X and Y units can be changed to Q or d-space values. Background
104can be subtracted. The legend can be removed from the plot.
105
106<BR clear=left><HR>
107Previous step: <A HREF="nickel5.html">
108Run POWPREF</A>
109<BR>
110Next step: <A HREF="nickel7.html">
111Setup for Least-Squares Refinement</A>
112
113
114<BR clear=left>
115<HR><p><a href="http://www.ncnr.nist.gov/staff/toby/">Brian Toby</a> (<a href="mailto:brian.toby@nist.gov">Brian.Toby@NIST.GOV</a>)
116<BR clear=left>
117$Revision: 209 $ $Date: 2009-12-04 23:02:13 +0000 (Fri, 04 Dec 2009) $
118</body>
119</html>
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