Dialog Box - called from: Symmetry Dialog
This symmetry option, for point symmetry only, assumes that Cartesian axes are in use, although it will work in any structure with axes at right angles. It is the only option applicable to non-crystallographic symmetry, and it can be used if desired in any other case. However, it is usually easier to use one of the other options for crystallographic symmetry.
This option requires a file containing the Cartesian symmetry matrices. The auxiliary program SYMGRP writes files which are normally given the suffix.SYM. If you type the name into the edit box, give the full name of the symmetry file, including the.SYM suffix. Some such files, namely those for pentagonal (C5, S10, D5, C5v, C5h, D5h and D5d) and icosahedral (I and Ih) point groups, have already been provided. For other point groups, it will be necessary to run the auxilliary program SYMGRP to generate the file before running ATOMS.
The Get Symmetry button reads the file and fills out the symbol, number of matrices and centric/non-centric state, which are printed out below the file name.
The file name as entered in the edit box is saved in the data file for the structure. If the complete path is not given, the Cartesian symmetry file should be in the same directory as the data file. If the file cannot be found when the structure is calculated, you will get an error message and a chance to locate the file with a standard file dialog. The complete path name, as determined in this way or with the Browse button, will then be saved in the data file.
Obtaining SYMGRP. To get SYMGRP, download the demo for SHAPE from www.shapesoftware.com - SYMGRP is in a sub-folder.