Volmer-Stranski-Becker-Doring

With this model in mind we may adapt the Volmer-Stranski-Becker-Doring theory of homogeneous nucleation in a supersaturated vapor to the problem of nucleation of a new crystalline phase II in the interior of an unstable crystalline phase I. Progressive clustering of kinetic units occurs to form embryos ... 

By making use of Volmer s equations some attempts have been made by Becker and Doring (1935), Stranski and Totomanov (1933), and Davey (1993) to explain the Rule in kinetic terms. In doing this, it becomes apparent that the situation is by no means as clear cut as Ostwald might have us believe. Figure 2.11 shows the three possible simultaneous solutions of the nucleation equations which indicate that by careful control of the occurrence domain there may be conditions in which the nucleation rates of two polymorphic forms are equal, and hence their appearance probabilities are nearly equal. Under such conditions we might expect the polymorphs to crystallize concomitantly (see Section 3.3). In other cases, there is a clearer distinction between kinetic and thermodynamic crystallization conditions, and that distinction may be utilized to selectively obtain or prevent the crystallization of a particular polymorph. 

Volmer and Weber [2.14], Farkas [2.15] and Kaischew and Stranski [2.16-2.18] were the first who examined the stationary nucleation kinetics and derived theoretical expressions for the stationary nucleation rate. However, in this Chapter we shall present the results of the more rigorous treatments of Becker and Doring [2.6] and ofZeldovich [2.19] and Frenkel [2.20] who laid the foundations of the contemporary classical nucleation theory (see also [2.V-2.9] and [2.21-2.24]). For the sake of simplicity we shall neglect both the line tension effects (equations (1.42) and (1.70)) and the dependence of the specific free surface energy on the size of the clusters (equation (1.43). 

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