This data block contains the symmetry operations under which the unit cell is invariant. Each operation is represented by a 3 × 3 array. The data block has the following format:
%BLOCK SYMMETRY_OPS R11 R21 R31 R12 R22 R32 R13 R23 R33 T1 T2 T3 R11 R21 R31 R12 R22 R32 R13 R23 R33 T1 T2 T3 . . . %ENDBLOCK SYMMETRY_OPS
Each of the first three lines contains 3 entries representing a row of a 3 × 3 array. These represent one symmetry rotation. The three entries on the following line contain the translation associated with this rotation.
If no symmetry is specified in the cell definition file, the default is for no symmetry to be applied.
%BLOCK SYMMETRY_OPS . . . -1.0000000000 0.0000000000 0.0000000000 0.0000000000 -1.0000000000 0.0000000000 0.0000000000 0.0000000000 1.0000000000 0.5000000000 0.0000000000 0.5000000000 . . . %ENDBLOCK SYMMETRY_OPS
CASTEP keyword glossary
CASTEP cell keywords and data blocks