Minimal energy packings of nearly flexible polymers

We extend recent studies of the minimal energy packings of short flexible polymers with hard-core-like repulsions and short-range attractions to include bond-angle interactions with the aim of describing the collapsed conformations of `colloidal' polymers. We find that flexible tangent sticky-hard-sphere (t-SHS) packings provide a useful perturbative basis for analyzing polymer packings with nonzero bending stiffness only for small ratios of the stiffnesses for the bond-angle and pair interactions, $k_b^ crit/k_c ≤sssim 0.01$ for $N<10$, and the critical ratio decreases with the number of monomers $N$. Thus we argue that future studies should not use flexible t-SHS minimal energy packings as a reference set to enumerate and characterize the structural and mechanical properties of polymer packings with finite bending stiffness.