Please keep the mail list in the thread.
I’m saying that if you have a triclinic box that is
periodic in x-y but not in z, that there is no
“force” in the system that will maintain the tilt
in z (i.e. xz or yz). If the atoms want to move so
that the crystalline planes have no tilt in z, then
they will. It’s only a periodic boundary and interaction
with image atoms across that boundary that will
maintain the tilt in the atoms.
Maybe that’s fine for your model, maybe not. You’ll
have to figure out what you want.
You can’t use fix deform in non-periodic dimensions.
Where you can use it, it has options to update the tilt
factor when elongating or not, as does fix npt (see the
scale keywords).
Steve