[lammps-users] freezing molecules in a simulation

Hello,
I am trying to run a MD simulation on the interface between bulk epoxy and graphite sheets. To do this, I am trying to freeze the graphite sheets in a planar conformation while still allowing them to contribute to the overall energy of the system. I was thinking that the fix freeze command would work for this, but I have no idea how to use it. Is it possible to freeze only a certain portion of a simulation? Can I declare the carbon atoms in the graphite sheet as their own atom type, and then freeze only this atom type? Any help would be greatly appreciated!!

-Cameron

Fix freeze (as well as other fixes) are applied to a group of
atoms. A "group" can be many different things - see the group command.
You can put just your graphite atoms into a group and then freeze them,
or use fix setforce to zero the force on them, or just don't time integrate
those atoms.

Steve