Allen Erik C, Rutledge Gregory C
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 USA.
J Chem Phys. 2009 Jan 21;130(3):034904. doi: 10.1063/1.3055594.
Previously, we described a coarse-graining method for creating local density-dependent implicit solvent (DDIS) potentials that reproduce the radial distribution function (RDF) and solute excess chemical potential across a range of particle concentrations [E. C. Allen and G. C. Rutledge, J. Chem. Phys. 128, 154115 (2008)]. In this work, we test the transferability of these potentials, derived from simulations of monomeric solute in monomeric solvent, to mixtures of solutes and to solute chains in the same monomeric solvent. For this purpose, "transferability" refers to the predictive capability of the potentials without additional optimization. We find that RDF transferability to mixtures is very good, while RDF errors in systems of chains increase linearly with chain length. Excess chemical potential transferability is good for mixtures at low solute concentration, chains, and chains of mixed composition; at higher solute concentrations in mixtures, chemical potential transferability fails due to the nature of the DDIS potentials, in which particle insertion directly affects the interaction potential. With these results, we demonstrate that DDIS potentials derived for pure solutes can be used effectively in the study of many important systems including those involving mixtures, chains, and chains of mixed composition in monomeric solvent.
此前，我们描述了一种粗粒化方法，用于创建局部密度依赖的隐式溶剂（DDIS）势，该势可在一系列粒子浓度范围内重现径向分布函数（RDF）和溶质过量化学势[E. C. 艾伦和G. C. 拉特利奇，《化学物理杂志》128, 154115 (2008)]。在这项工作中，我们测试了这些源自单体溶剂中单体溶质模拟的势对溶质混合物以及同一单体溶剂中溶质链的可转移性。为此，“可转移性”指的是势在无需额外优化的情况下的预测能力。我们发现，RDF对混合物的可转移性非常好，而链系统中的RDF误差随链长线性增加。过量化学势的可转移性在低溶质浓度的混合物、链以及混合组成的链中表现良好；在混合物中溶质浓度较高时，由于DDIS势的性质，化学势的可转移性失效，在这种势中粒子插入会直接影响相互作用势。通过这些结果，我们证明了为纯溶质推导的DDIS势可有效地用于研究许多重要系统，包括那些涉及单体溶剂中的混合物、链以及混合组成的链的系统。
