Symmetry

The current implementation of symmetry in ADFinput is still in a very early stage: using it is somewhat complicated, and sometimes it does not work as expected.

First you need to define the point group that you want to use for your molecule. You do this by selecting the group name from the symmetry pull-down menu (initially the menu reads 'Nosym').

Next you need to define one or two operators for the selected group. In the symmetry menu you can see what operators you need to define.

Make sure that the (symmetry) origin of your molecule is set correctly (use the SetOrigin menu command).

1 atom selected: this defines the axis through center of molecule and the selected atom. This is the axis that will be used when you define a rotation axis. When you use it to define a mirror plane, the plane perpendicular to this axis through the origin of your molecule will be used.

2 atoms selected: defines an axis that will be used either as rotation axis, or as normal axis to a mirror plane through the origin.

3 atoms selected: defines a plane that will be used as mirror plane (shifted to the origin if required), or defines an axis for rotation (through the origin, in the direction of the normal vector of the plane).

Next you can use the symmetry commands:

Symmetrize: try to update the coordinates of the current atoms so that the molecule indeed has the required symmetry. Warning: if atoms are missing this will be resolved by moving equivalent atoms to the origin ...

Add symmetry equivalent atoms: generate all missing symmetry equivalent atoms to produce a molecule with the required symmetry. The existing atoms may be slightly moved to enforce perfect symmetry.