Department of Systems Biology, Columbia University, New York City, New York 10032, USA.
Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, USA.
J Chem Phys. 2017 Oct 28;147(16):164901. doi: 10.1063/1.4993178.
Quantifying the statistics of occupancy of solvent molecules in the vicinity of solutes is central to our understanding of solvation phenomena. Number fluctuations in small solvation shells around solutes cannot be described within the macroscopic grand canonical framework using a single chemical potential that represents the solvent bath. In this communication, we hypothesize that molecular-sized observation volumes such as solvation shells are best described by coupling the solvation shell with a mixture of particle baths each with its own chemical potential. We confirm our hypotheses by studying the enhanced fluctuations in the occupancy statistics of hard sphere solvent particles around a distinguished hard sphere solute particle. Connections with established theories of solvation are also discussed.
定量描述溶剂分子在溶质附近的占据统计对于理解溶剂化现象至关重要。在宏观巨正则框架中，使用单个化学势来表示溶剂浴，无法描述溶质周围小溶剂化壳层中的数波动。在本通讯中，我们假设分子大小的观察体积（如溶剂化壳层）最好通过将溶剂化壳层与具有各自化学势的粒子浴混合物耦合来描述。我们通过研究硬球溶剂粒子在突出的硬球溶质粒子周围的占据统计增强波动来验证我们的假设。还讨论了与已建立的溶剂化理论的联系。
