The Autoindex feature uses a grid search to guess at a set of lattice
parameters for a particular symmetry. Note that the results obtained are just a "hint". It is
not guaranteed that Datasqueeze will find any solution at all, or that the solution it finds is unique or the best solution. Nevertheless,
this feature can often be useful in indexing a powder diffraction pattern.
This panel is brought up by clicking on the "Autoindex" button in the "Calculate Peak Positions" window.
New yellow or orange cursors will also appear in the plot image.
- Use the "Peaks" drop-down menu to indicate how many peaks in the plot you wish to use for indexing.
Then drag the cursors so they lie directly above or below the centers of the peaks.
- Set the "Precision" drop-down to the precision with which you the cursors accurately reflect the true peak positions (default 1%).
- Click "Start". After a while, the optimized lattice parameters will appear in the window and the
indexing lines on the plot will be set to the obtained values. (This may take between several seconds for a high-symmetry
lattice, such as 2D hexagonal, and tens of minute for a low-symmetry lattice, such as Simple Monoclinic).
- Troubleshooting:
- If Datasqueeze says that it cannot find a match, or if it finds a match with what you consider to be
unphysically large lattice parameters, it is most likely that you are using the wrong lattice.
However, it is also possible that one or more of the cursors is not properly aligned, or that you have the precision set to too small a value.
- If the indexed lines do not seem to agree very well with the peak positions, you should set the precision to a smaller value.
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