标题： 通过改进参考系统的描述，在SAFT中引入多体效应。 I. 参考系统中团簇积分的平均活性修正 显示英文标题

标题： Incorporating multi-body effects in SAFT by improving the description of the reference system. I. Mean activity correction for cluster integrals in the reference system

摘要： 具有可多次在任意方向相互作用的溶质的分块胶体粒子系统是分块胶体混合物的一个有用模型。 尽管相互作用简单，但由于存在多体相关性，预测此类系统的热力学性质仍然是一个挑战。 早先，Marshall 和 Chapman 为这类系统开发了一个多体公式，在其中使用硬球溶剂分子在硬球溶质定义的内壳（或配位体积）中的团簇分区函数作为统计关联流体理论形式中的参考。 这些分区函数的多体贡献是通过忽略体相溶剂获得的，因此该理论的应用仅限于低系统密度。 我们从溶液的准化学理论中获得灵感，这些分区函数以团簇形成的平衡常数的形式出现，我们开发了一种方法来考虑多体相关性，包括体相溶剂的影响。 我们通过硬球参考的模拟获得排出内壳的自由能，这是准化学理论中的化学贡献。 这个化学贡献反映了在体相介质存在的情况下参考中的结合情况。 然后通过一个平均活性因子来增强气相分区函数，该因子被调整以再现化学贡献。 我们证明更新后的分区函数提供了一个改进的参考，能够更好地捕捉溶剂在溶质周围的分布，直至高系统密度。 使用这个更新后的参考，我们发现该理论更能描述胶体在实际系统中的结合状态和过量化学势。 显示英文摘要

摘要： A system of patchy colloidal particles interacting with a solute that can associate multiple times in any direction is a useful model for patchy colloidal mixtures. Despite the simplicity of the interaction, because of the presence of multi-body correlations predicting the thermodynamics of such systems remains a challenge. Earlier Marshall and Chapman developed a multi-body formulation for such systems wherein the cluster partition function for the hard-sphere solvent molecules in a defined inner-shell (or coordination volume) of the hard-sphere solute is used as the reference within the statistical association fluid theory formalism. The multi-body contribution to these partition functions are obtained by ignoring the bulk solvent, thus limiting the applicability of the theory to low system densities. Deriving inspiration from the quasichemical theory of solutions where these partition functions occur in the guise of equilibrium constants for cluster formation, we develop a way to account for the multi-body correlations including the effect of the bulk solvent. We obtain the free energy to evacuate the inner-shell, the chemistry contribution within quasichemical theory, from simulations of the hard-sphere reference. This chemistry contribution reflects association in the reference in the presence of the bulk medium. The gas-phase partition functions are then augmented by a mean activity factor that is adjusted to reproduce the chemistry contribution. We show that the updated partition function provides a revised reference that better captures the distribution of solvent around the solute up to high system densities. Using this updated reference, we find that theory better describes both the bonding state and the excess chemical potential of the colloid in the physical system.