[Wien] spacegroup p31m

[Michael Gurnett]

Hello. 

I have a unit cell (slab with vacuum) that is spacegroup 157 p31m. All the atoms when viewed look ok, but when I look at the forces on the atoms from within analyse it apears that a number of the z positions are locked due to symmetry (forces show 0.0000). How can this be true? If I look at the space group all z positions should be free. What could the possible reasons for this be. 

Michael
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20050908/406e7594/attachment.html