Classical Theory of Nucleation in a One-Component System without Strain Energy

1 Classical Theory of Nucleation in a One-Component System without Strain Energy 

Consider a one-component system that consists initially of a total of Af atoms of a parent a phase that is metastable with respect to the formation of an equilibrium 

When the interfacial energy depends on the inclination of the interface and 7 is therefore anisotropic, Eq. 19.1 does not apply. In this case, the cluster will minimize its total interfacial energy by adopting its Wulff shape (Section C.3.1), which may be fully faceted or made up of faceted and smoothly curved regions. Several characteristic shapes are shown in Fig. 19.2. The interfacial-energy term in Eq. 19.1 can then be expressed as the sum of the interfacial energies of the various faceted or smoothly curved patches that make up the entire closed interface and 

Fi gure 19.2 Calculated nucleus shapes for homogeneous nucleation of an f.c.c. phase in 

JIn systems with fixed stoichiometry such as CO2 or polyvinyl chloride, N would be the number of molecules. In this chapter we refer to atoms, but molecular systems can be treated analogously. 

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