Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 8, 64287 Darmstadt, Germany.
J Chem Theory Comput. 2020 Mar 10;16(3):1431-1447. doi: 10.1021/acs.jctc.9b01088. Epub 2020 Feb 19.
We cast the acceleration of the dynamics of coarse-grained polymer models, or, conversely, the decrease in monomer friction in terms of excess entropy differences between different coarse-grained resolutions. From a simple bead-spring model of unentangled polymers in a melt, we systematically derive two coarse-grained models of different resolutions, for which exact excess entropies are obtained through a carefully carried out two-step thermodynamic integration. We found that the excess entropy differences between the coarser and finer models correlated well with the logarithm of the ratio of dynamical properties quantifying the acceleration upon changing the model resolution. Moreover, we have considered how well the two-body approximation to the excess entropy is correlated and also the scaling of the excess entropy in the analysis. Our results indicate that the acceleration brought about by coarse-graining can be understood in terms of excess entropy differences for unentangled polymers also. The correlations presented in this work may open new possibilities to a posteriori correct the coarse-graining dynamics by a simple route.
我们根据不同的粗粒分辨率之间的过剩熵差异来描述粗粒聚合物模型的动力学的加速，或者相反，来描述单体摩擦的减小。从无缠结聚合物熔体的简单珠-簧模型出发，我们系统地推导出两种不同分辨率的粗粒模型，通过精心进行的两步热力学积分，我们得到了它们的精确过剩熵。我们发现，较粗和较细模型之间的过剩熵差异与动力学特性的对数很好地相关，该动力学特性定量描述了改变模型分辨率时的加速。此外，我们还考虑了如何很好地关联二体近似过剩熵以及在分析中过剩熵的标度。我们的结果表明，无缠结聚合物的过剩熵差异也可以用来理解粗粒化所带来的加速。本文提出的相关性可能为通过简单的途径对粗粒化动力学进行后验修正开辟了新的可能性。
