Highly constrained polymer dynamics with an enhanced bond-fluctuation model

We introduce a generalization to the bond-fluctuation model for simulating polymer dynamics in a highly constrained environment. The technique is applied to the quenching of self-attracting polymer chains which demonstrates a three-fold collapse. Both the extent and dynamics of the collapse are greatly enhanced by using the generalized bond-fluctuation model where the bond length $l = \sqrt{8}$ (in units of the lattice spacing) is explicitly utilized. We also show that lattice effects in dense melts ($\phi > 0.5$) are alleviated with this enhancement. Efficiency is maintained by implementing a simple check to prevent phantom chain dynamics.