Intrachain interactions

You can probably define each of the six nearest neighbour atoms of one chain as specific types and set lj coefficients to zero.

Arun

You can probably define each of the six nearest neighbour atoms of one
chain as specific types and set lj coefficients to zero.

i don't think that that can work unless you give a different type to
each atom, as this doesn't differentiate between inter- and
intra-molecular interactions.
it is more likely to make it work through adding dummy bonds instead,
which would turn selected neighbors beyond 1-4 back into 1-2
neighbors. that can be tricky, too. it is probably best to set
special_bonds lj/coul to 0.0 1.0 1.0 and then define all exclusions
explicitly, e.g. using bond style hybrid with bond style zero.
it is probably beneficial to identify the desired exclusion through
some kind of program or script, as it can be tedious and very error
prone to do it manually.

axel.