(545i) Separation of Enthalpic and Entropic Contributions to Coarse-Grained Potentials for Resolving Dynamics Using the Iterative Boltzmann Inversion (IBI) Method

In recent work [J. Chem. Phys. 154,084114 (2021)], we studied a CG model that aims to preserve both chemical specificity and dynamics of a polymer melt. We used iterative Boltzmann inversion (IBI) to parameterize the conservative potential and reproduce the structural distributions of the melt from all-atom (AA) reference simulations, and Langevin dynamics to introduce a dissipative potential as a means to recover the AA dynamics. Using this method, we found we could repair the dynamics of various diffusive measures with about a 20% variation or less in the friction parameter. Here we further our analysis this CG model by examining the influence of Langevin friction on the dynamics of the individual potentials. Various dynamic correlation functions are used to quantify and compare the dynamics of the bonded and pair potentials for the diffusion corrected CG models and the AA reference systems. This leads to an integrated approach for recovering both structure and dynamics within the scope of an IBI based parametrization by properly accounting for separate enthalpic and entropic contributions to the potentials. The effect of the refined potentials on property predictions are analyzed.