The Configurational Partition Function: Molecular Distribution Functions

Abstract

The chapter introduces the very important notions of configurational partition function and of molecular distribution functions. They are at the basis of the notion of radial distribution function which, in turn, is at the cornerstone of our purpose (which is to get some insight about the significance of an activity). The radial distribution function enters, indeed, in the theoretical expressions of thermodynamic quantities, among which the chemical potential.

The chapter is essentially devoted to definitions. The first given one is that of the configuration integral. Other defined functions are the basic density distribution function, the molecular distribution functions (both the specific and the generic ones), the pair molecular distribution functions, and the pair correlation function with the radial distribution function. The chapter mentions only one theoretical study. It concerns the molecular distribution functions of monoatomic fluids. Some aspects of the theoretical study of the radial distribution function are postponed to the following chapter.

Most of the theoretical considerations mentioned in this chapter are developed within the framework of the canonical ensemble and, only, the case of pure liquids is investigated.