fix indent for a specific group of atoms

Dear Lammps,

I am trying to create a cylindrical indenter in a polymer+ionic system. My intention is to repel only polymer but do nothing to ions inside the cylindrical tube. I am using the following fix to this purpose:

group polymer type 1 2 3 4
group ions type 5 6 7
fix fixpore polymer indent 10.0 cylinder z 0.0 0.0 10 units box

However, instead of repelling the polymer alone, all of the atoms were seen to repel with the above fix. Does “fix indent” work for a specific group of atoms ?


yes, fix indent only operates on atoms in the group.