chapter  60
7 Pages

Comparison of the properties of equilibrium and metastable drops

The examples in Figs. 59.4-59.6 demonstrate the inadequacy of the thermodynamic conditions [22] for a unique relationship between the degree of supersaturation and the drop radius.

To select a single value of qm, an additional condition is necessary, which is absent in thermodynamic conditions [22]. For example, if R = const is chosen to be the minimum of all the values of σ(qm) for the admissible values of Pmet/Ps, then such a dependence of σmin(R) is shown in Fig. 59.7 for a wide range of drop sizes. This dependence largely coincides with the dependence obtained in [24, 27]: at low temperatures the value of the surface tension abruptly exceeds the volume value of σb and gradually decreases to it, and at high temperatures, σb gradually approaches. Another way to select a single value from the range of admissible Pmet values is to choose a pressure for which qL = qm = qe, where qe is the equimolecular position of the reference surface. In this case the values of σ(qe) differ somewhat from the values of σ(qm), but the discrepancies are small and commensurate with other methods of calculating σ [24,27].