PLATON Manual
The n.ijk Symmetry Operation on Input
Atomic coordinates as input will be transformed in general by symmetry operations following certain rules. In the default
automatic mode this will result in a connected set with residues properly positioned within the unit cell range. The symmetry
operation applied to the input data will be listed under the header trans in the atomic coordinates listing and is encoded as
n.ijk. n stands for the number of the symmetry operation as specified on the first page of the output listing and ijk for the
unit cell translations in the three directions relative to 555: ijk=564 means 1 positive translation in the b direction, 1
negative translation in the c direction and none in the a direction.
The automatic mode transformation may be overruled for a given atom by preceding the data for that particular atom by a
TRNS instruction e.g. TRNS 3.564. This facility may be used to determine the part of the molecule that is to be considered as
the asymmetric part of a symmetrical molecule.
The transformation to be applied only to the first atom as a starting point of a new residue can be forced with a negative
symmetry transformation code e.g. TRNS -5.354. Its position in the input stream determines the atoms to which it will apply. The
input stream may contain several of such instructions, each apply to the atoms that follow until overruled by a new one. Their
effect will only be on atoms that are choosen to start a new residue.