U.S. Department of Energy Office of Scientific and Technical Information
A comparative study of coarse-graining methods for polymeric fluids: Mori-Zwanzig vs. iterative Boltzmann inversion vs. stochastic parametric optimization
We construct effective coarse-grained (CG) models for polymeric fluids by employing two coarse-graining strategies. The first one is a forward-coarse-graining procedure by the Mori-Zwanzig (MZ) projection while the other one applies a reverse-coarse-graining procedure, such as the iterative Boltzmann inversion (IBI) and the stochastic parametric optimization (SPO). More specifically, we perform molecular dynamics (MD) simulations of star polymer melts to provide the atomistic fields to be coarse-grained. Each molecule of star polymer with internal degrees of freedom is coarsened into a single CG particle and the effective interactions between CG particles can be either evaluated directly from microscopic dynamics based on the MZ formalism, or obtained by the reverse methods, i.e., IBI and SPO. The forward procedure has no free parameters to tune and recovers the MD system faithfully. For the reverse procedure, we find that the parameters in CG models are not interchangeable. If the free parameters are properly selected, the reverse CG procedure also yields an effective potential. Furthermore, we explain how an aggressive coarse-graining procedure introduces many-body effect, which makes the pairwise potential invalid for the same system at densities away from the training point. From this work, general guidelines for coarse-graining of polymeric fluids can be drawn.
Li, Zhen, et al. "A comparative study of coarse-graining methods for polymeric fluids: Mori-Zwanzig vs. iterative Boltzmann inversion vs. stochastic parametric optimization." Journal of Chemical Physics, vol. 145, no. 4, Jul. 2016. https://doi.org/10.1063/1.4959121
Li, Zhen, Bian, Xin, Yang, Xiu, & Karniadakis, George Em (2016). A comparative study of coarse-graining methods for polymeric fluids: Mori-Zwanzig vs. iterative Boltzmann inversion vs. stochastic parametric optimization. Journal of Chemical Physics, 145(4). https://doi.org/10.1063/1.4959121
Li, Zhen, Bian, Xin, Yang, Xiu, et al., "A comparative study of coarse-graining methods for polymeric fluids: Mori-Zwanzig vs. iterative Boltzmann inversion vs. stochastic parametric optimization," Journal of Chemical Physics 145, no. 4 (2016), https://doi.org/10.1063/1.4959121
@article{osti_1356514,
author = {Li, Zhen and Bian, Xin and Yang, Xiu and Karniadakis, George Em},
title = {A comparative study of coarse-graining methods for polymeric fluids: Mori-Zwanzig vs. iterative Boltzmann inversion vs. stochastic parametric optimization},
annote = {We construct effective coarse-grained (CG) models for polymeric fluids by employing two coarse-graining strategies. The first one is a forward-coarse-graining procedure by the Mori-Zwanzig (MZ) projection while the other one applies a reverse-coarse-graining procedure, such as the iterative Boltzmann inversion (IBI) and the stochastic parametric optimization (SPO). More specifically, we perform molecular dynamics (MD) simulations of star polymer melts to provide the atomistic fields to be coarse-grained. Each molecule of star polymer with internal degrees of freedom is coarsened into a single CG particle and the effective interactions between CG particles can be either evaluated directly from microscopic dynamics based on the MZ formalism, or obtained by the reverse methods, i.e., IBI and SPO. The forward procedure has no free parameters to tune and recovers the MD system faithfully. For the reverse procedure, we find that the parameters in CG models are not interchangeable. If the free parameters are properly selected, the reverse CG procedure also yields an effective potential. Furthermore, we explain how an aggressive coarse-graining procedure introduces many-body effect, which makes the pairwise potential invalid for the same system at densities away from the training point. From this work, general guidelines for coarse-graining of polymeric fluids can be drawn.},
doi = {10.1063/1.4959121},
url = {https://www.osti.gov/biblio/1356514},
journal = {Journal of Chemical Physics},
issn = {ISSN 0021-9606},
number = {4},
volume = {145},
place = {United States},
publisher = {American Institute of Physics (AIP)},
year = {2016},
month = {07}}
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF);
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division
Grant/Contract Number:
AC05-76RL01830; AC02-06CH11357; AC05-00OR22725
OSTI ID:
1356514
Alternate ID(s):
OSTI ID: 22679038 OSTI ID: 1272642
Report Number(s):
PNNL-SA--116567; KJ0401000
Journal Information:
Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 4 Vol. 145; ISSN 0021-9606
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 372, Issue 2021https://doi.org/10.1098/rsta.2013.0389