A model of interacting clusters for microscopic nucleation theory

A model is suggested for the microscopic theory of homogeneous nucleation. This model, which will be referred to as the interacting monomers and clusters, is composed of different concentrations of clusters of different sizes. In this model, in addition to the internal structure for each cluster which is similar to the atomistic model, the monomer–monomer interaction and monomer–cluster interaction are taken into account. The calculation of the configuration integral is made possible by extending the method of correlation function to apply to the interacting monomers and clusters model. The formation energy of a cluster and the equilibrium concentration of clusters, which are necessary for obtaining the nucleation rate, have been calculated. These new expressions for the equilibrium concentration of clusters and the formation energy of a cluster reduce to the same form used in the atomistic model, when there is no interaction between monomers and clusters. Additionally, this model reduces to a system of an imperfect gas when there are only monomers in the system. The formation energy of a cluster in the interacting monomers and clusters and in the atomistic model for the Lennard-Jones potential has been studied.