Reverse Mapping of Coarse-Grained Polyethylene Chains from the Second Nearest Neighbor Diamond Lattice to an Atomistic Model in Continuous Space

A high coordination lattice was recently introduced for the simulation of coarse-grained rotational isomeric state (RIS) model chains. This second nearest neighbor diamond (2nnd) lattice is formed by connecting every other site on a tetrahedral lattice. Monte Carlo simulations of polyethylene (PE) melts have recently been performed on the 2nnd lattice by incorporating the intramolecular short range interactions from the RIS model and the long range interactions using a potential derived from an averaging procedure of the Mayer function in the expansion for the second virial coefficient. In the present work, the reverse mapping of specific snapshots from the coarse-grained PE melt back to the fully atomistic representation in continuous space is demonstrated. Reverse mapping is, essentially, determining the location of intermediate backbone atoms that are not represented on the 2nnd lattice but exist on the diamond lattice. In certain situations, the new locations of two intermediate atoms may coincide, le...