ABSTRACT
This chapter deals with perturbation theories for simple fluids and solids based, in one way or another, on series expansions of the Helmholtz free energy. Some of these expansions lead, from a different viewpoint, to certain theories cited in Section 4.4 within the context of integral equation perturbation theories. This chapter includes the analysis of the performance of some of these theories for several potential models as compared with the simulation data.
