On 13/03/2018 20:12, Ana Luísa Moreira de Carvalho wrote:
You can find the tool “Fixed Atoms” in the Refinement Toolbar (the side menu). Just click Fix Atom and then
click the atom(s) you wish to fix. It won’t move in real space refinement or in regularisation.
That's right, Ana Luísa.
And for the record, it's often useful to move fixed atoms. Use Ctrl Left-mouse click and drag. So Fixed
Atoms move when nothing else moves and stay still when everything else refines. Paradoxical maybe, but
useful. I use it when I have to assert my authority over recalcitrant atoms.