[lammps-users] How can I fix my substrate efficiently to remain solid?

Dear Friends,

I am simulating a simple 2 dimensional Model, which consist of 2 groups:
1- liquid group
2- susbtrate group, which is sorounded by liquid group

I am going to fix a substrate group. I am looking for the best fix command for fixing the substrate group. this fix command should avoid moving the substrate group (being solid during simulation). Moreover, atoms in both substrate and liquid groups should interact with each other. Since, I am going to watch solidification of liquids on the substrate.So, I have applied these commands in my input file:

If you don't want the solid to move at all, then don't time integrate it.