[lammps-users] creating polymer beads!

I have been trying to set a polymer flow in a rectangular geometry. I have gone through the program ‘chain.f’ and I don’t understand how the excluded volume effect is implemented in this program i.e., when initializing the polymer chains in the box how the overlapping of different beads is prevented. Can anyone make this clear to me?



I haven’t used chain.f with LAMMPS for creating polymer. But to get rid of badly overlapped atoms from initial built you need to use some softer potentials initially to relax the chains. Also building a low density structure and then relaxing and compressing it alternatively with annealing is recommended for getting the final equilibrated structure. Hope this helps.


The chain.f tool doesn't worry about excluded volume or overlaps.
It just grows individual chains so that successive beads don't overlap.

As Arnab suggested, you need to take that initial state and run
dynamics with a soft potential, or a force-limited timestep (see
pair_style soft or fix nve/limit) to get an unoverlapped system.