[lammps-users] Extending special_bonds beyond 1-4

The neigh_modify exclude group command will turn off pairwise
interactions within a molecule (i.e. within the same polymer chain).

Steve

Hi, Steve.

Reading the the syntax on the help pages, do you mean

neigh_modify exclude molecule all ?

I should have mentioned - In my case, N is less than the molecular weight of the polymer.

In other words, I’m trying to turn off pairwise interactions between beads, on the same polymer, that are separated by less than N beads along the chain.

Thanks.

GS.

I should have mentioned - In my case, N is less than the molecular weight of the polymer.

In other words, I'm trying to turn off pairwise interactions between beads, on the same polymer, that are separated >by less than N beads along the chain.

Neigh_modify won't work then. I assumed you wanted to turn off all pairwise
interactions within the entire chain.

There is no easy way to do what you are asking. You might have to write
your own pair style that uses a normal neigh list (only excluding 1-2,1-3,1-4)
and looks at some other value to decide to throw out (or weight) 1-5, 1-6, etc.
E.g. you could store the chain position in the molecule ID and examine that
to determine how many hops apart 2 monomers are. The fix bond/swap does
something like that.

Steve