
6
Free Energy Perturbation
Theories for Simple
Fluids and Solids
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.
6.1 SERIES EXPANSION OF THE FREE ENERGY
Let us consider a spherically symmetric pair potential u(r) that can be split into two
contributions, ...