In this work, we propose a novel approach for obtaining thermodynamic properties of lattice fluids based on local compositions. Rather than imposing a prescribed function for local compositions (e.g., the Boltzmann distribution as in most conventional local composition models), the local composition is determined based on minimization of free energy of the system in this new approach. This is made possible by expressing the potential energy and entropy (all possible arrangements of species on the lattice) of a system in terms of a given bulk and local composition. We show that the model resulted from this approach coincides with the well-known Ising model for a binary mixture in one-dimension with an interchangeable chemical reaction. However, this new model is applicable even when the species are not interchangeable, and therefore the free energy surface at all possible composition can be obtained. In the infinitely large lattice, this model also coincides with the COSMO-SAC model. This model could serve as a valuable basis for development of local composition models of more complicated systems.

在这项工作中，我们提出了一种基于局部成分获得晶格流体热力学性质的新方法。而不是对本地作品施加规定的功能（例如，如大多数传统局部组成模型中的玻耳兹曼分布，在这种新方法中，基于系统自由能的最小化来确定局部组成。通过以给定的体积和局部组成来表示系统的势能和熵（晶格上所有可能的物种排列），使之成为可能。我们证明了这种方法所产生的模型与众所周知的伊辛模型的一维二元混合物具有可互换的化学反应相吻合。但是，即使物种不可互换，该新模型仍然适用，因此可以获得所有可能组成的自由能表面。在无限大的晶格中，该模型也与COSMO-SAC模型重合。