Setup of the unit cell symmetry

The symmetry of the system is another important input to Fleur. It is specified by providing a list of symmetry operations. Usually, these operations are generated by the input-generator by inspection of the cell and atomic input.

For certain calculations you might want to modify the operations and for example remove symmetry operations. While this is easily possible by removing operations from the list in inp.xml you should be careful not to remove operations that map equivalent atoms onto each other within an atom group. If you remove such operations you have to adjust the assignment of atoms to groups.

The usual way to specify symmetry operations is by using the corresponding '' XML tag.

      <symmetryOperations>
<symOp>
<row-1>1 0 0 .0000000000</row-1>
<row-2>0 1 0 .0000000000</row-2>
<row-3>0 0 1 .0000000000</row-3>
</symOp>
<symOp>
<row-1>-1 0 0 .0000000000</row-1>
<row-2>0 1 0 .0000000000</row-2>
<row-3>0 0 1 .0000000000</row-3>
</symOp>
<symOp>
<row-1>1 0 0 .0000000000</row-1>
<row-2>0 -1 0 .0000000000</row-2>
<row-3>0 0 1 .0000000000</row-3>
</symOp>
<symOp>
<row-1>-1 0 0 .0000000000</row-1>
<row-2>0 -1 0 .0000000000</row-2>
<row-3>0 0 1 .0000000000</row-3>
</symOp>
<symOp>
<row-1>0 -1 0 .5000000000</row-1>
<row-2>-1 0 0 .5000000000</row-2>
<row-3>0 0 1 .0000000000</row-3>
</symOp>
<symOp>
<row-1>0 -1 0 .5000000000</row-1>
<row-2>1 0 0 .5000000000</row-2>
<row-3>0 0 1 .0000000000</row-3>
</symOp>
<symOp>
<row-1>0 1 0 .5000000000</row-1>
<row-2>-1 0 0 .5000000000</row-2>
<row-3>0 0 1 .0000000000</row-3>
</symOp>
<symOp>
<row-1>0 1 0 .5000000000</row-1>
<row-2>1 0 0 .5000000000</row-2>
<row-3>0 0 1 .0000000000</row-3>
</symOp>
<symOp>
<row-1>1 0 0 .5000000000</row-1>
<row-2>0 1 0 .5000000000</row-2>
<row-3>0 0 -1 .0000000000</row-3>
</symOp>
<symOp>
<row-1>-1 0 0 .5000000000</row-1>
<row-2>0 1 0 .5000000000</row-2>
<row-3>0 0 -1 .0000000000</row-3>
</symOp>
<symOp>
<row-1>1 0 0 .5000000000</row-1>
<row-2>0 -1 0 .5000000000</row-2>
<row-3>0 0 -1 .0000000000</row-3>
</symOp>
<symOp>
<row-1>-1 0 0 .5000000000</row-1>
<row-2>0 -1 0 .5000000000</row-2>
<row-3>0 0 -1 .0000000000</row-3>
</symOp>
<symOp>
<row-1>0 -1 0 .0000000000</row-1>
<row-2>-1 0 0 .0000000000</row-2>
<row-3>0 0 -1 .0000000000</row-3>
</symOp>
<symOp>
<row-1>0 -1 0 .0000000000</row-1>
<row-2>1 0 0 .0000000000</row-2>
<row-3>0 0 -1 .0000000000</row-3>
</symOp>
<symOp>
<row-1>0 1 0 .0000000000</row-1>
<row-2>-1 0 0 .0000000000</row-2>
<row-3>0 0 -1 .0000000000</row-3>
</symOp>
<symOp>
<row-1>0 1 0 .0000000000</row-1>
<row-2>1 0 0 .0000000000</row-2>
<row-3>0 0 -1 .0000000000</row-3>
</symOp>
</symmetryOperations>


The symmetryOperations element allows to specify each symmetry operation directly. Each symmetry operation is given by a matrix of three rows and four columns, where the last column is a translation vector needed for nonsymmorphic symmetries. If the input file generator is invoked with the -explicit command line switch this form of declaring the symmetry operations is used in the inp.xml file.

Including the sym.xml file

As this list can be long it might be desired to provide the symmetry operations in a separate file. You can use the x-include option for this purpose.