Merging two data files in the write_data format or using a restart file - Simulating Polymer Welding

LAMMPS LAMMPS General Discussion
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1

Hello,

I am trying to simulate a welding process in lammps, which involves bringing two Kremer Grest polymer films together and allowing it to interdiffuse for a period of time. I have seen some papers doing this but I will appreciate Is there a way this can be done in lammps? I have tried using the read_data with the append keyword. I keep getting errors:
“ERROR: Subsequent read data induced too many bonds per atom (src/read_data.cpp:1342)
Last command: read_data input.lammps add append #final_traj.lmps add append #offset 0 0 # Film A equilibrated configuration”

If there is a lammps script that have done this, I will be happy if it can be shared.
A single polymer film (non - periodicity in one direction) contains 1 atom type and 1 bond type.

Thanks!

2

Please have a look at the “extra” keywords to read_data command — LAMMPS documentation

To explain, when the simulation box is created in LAMMPS, certain settings are locked in and cannot be changed afterwards, this includes the number of bonds per atom (bonds are not stored globally but stored with atoms that are bonded, so that the domain decomposition can work easily and bonds migrated between sub-domains with the atoms that are bonded).

I your special case, it might even work to simply reverse the order of data files to be combined.