Manipulating the Geometry

Note that the molecular geometry can be modified with the iman command of the internal coordinate menu described earlier, if internal coordinates has been defined. Another option is to select m in the geometry main menu which provides the following submenu:

CARTESIAN COORDINATE MANIPULATION MENU :
move   : TRANSLATE AND/OR ROTATE PART OF THE MOLECULE
inert  : MOVE MOLECULE SO THAT COORDINATE AXES BECOME
         PRINCIPAL AXES OF INERTIA
mback  : RESTORE PREVIOUS MOLECULAR GEOMETRY
dis    : DISPLAY MOLECULAR GEOMETRY
YOU MAY APPEND A QUESTION MARK TO ANY OF THESE COMMANDS
FOR FURTHER EXPLANATIONS.
HIT >return< OR USE ANY GEOMETRY COMMAND NOT IN THIS LIST
TO TERMINATE THIS MENU.
UPON TERMINATION THE MOLECULAR SYMMETRY WILL BE ENFORCED
ACCORDING TO SYMMETRY GROUP c3v .

The meaning of the commands inert and mback should be clear; command move allows you to manipulate the geometry of your molecule. After entering move, you will be asked to specify a set of atoms on which the command shall act. You can use this to manipulate only a part of your molecule, e.g. if you are building a structure from subunits and you want to adjust their relative arrangement. As long as you stay in this menu, the molecular symmetry needs not be correct (so that you can try different movements and/or rotations), but as soon as you leave it, the geometry will be symmetrized according to the present Schönflies symbol. After you specified the atomic set to be considered, you get the following information:

INPUT DIRECTION OF MOVEMENT OR LOCATION OF ROTATION AXIS
EITHER AS A COORDINATE TRIPLE SEPARATED BY BLANKS,
OR AS TWO ATOMIC INDICES SEPARATED BY KOMMA, OR x OR y OR z
OR ENTER ANY DISPLAY COMMAND FIRST OR & TO GO BACK

You can thus specify the direction of movement (or the rotational axis) in the form 0. 0. 1. or simply z (which both describes the z-axis) or 1.3256 -3.333 0.2218 for an arbitrary axis. If you want to specify an axis which is related to your molecule, you may also enter two atomic indices which define it. After having specified the axis, you have to enter the distance of movement and the angle of rotation. If you want to perform a simple rotation, enter 0 for the distance of movement and if you want to simply move your structure, enter 0 for the rotational angle.

You can leave this menu and return to the geometry main menu by hitting or by entering any command of the geometry main menu.