I believe this post is closely related to the problem I am encountering (a bit naive perhaps, sorry I am new to lammps).
Any answer/comment/advice is well appreciated. Thanks a lot.
Brief description of the problem (input and read file attached):
I want to sample the energy surface of 2 coarse grained interacting systems.
System 1 is composed of 3 atoms bonded between them (bond 1, bond 2 and angles 1).
System 2 is a single macroatom, interacting with a pair potential with the other 3 atoms in system 1.
To move system 2 around, I use a for loop over distance (no MD at the moment, in the long run I want to study transport properties).
So far everything is good.
I’d like to allow the bonded interaction in system 1 to be relaxed if the 4th atom comes too close to one of the atoms in system 1 (say < 4.5Ang from atom 2).
As suggested above, I try to define a new type (ID?) of bond, “3” in this case. The read_file.inp is modified as follow:
2 bonds -> 2 bonds # no change
2 bond types -> 3 bond types
Bond Coeffs # +1 line
1 200 2.0 -> 1 200 2.0
2 200 3.0 -> 2 200 3.0
#nothing -> 3 100 3.0
In the lammps.inp I would then insert:
fix bond_2_close 2 bond/break 1 2 4 4.5
fix bond_2_far 3 bond/create 1 2 4 4.5
but I cannot fix the group ID properly (already in the first line).
"ERROR: Could not find fix group ID (…)
Last command: fix bond_2_close 2 bond/break 0 2 4 4.5"
So the question is what is the group ID of the bond I am going to break and the one I would create afterwards?
Given that I am not interested in dynamics at this point, I also thought to nest a if condition on the value of the bond in the for loop over distance, but I would ultimately end up at the same point.
lammps.inp (1.37 KB)
read_file.in (457 Bytes)