Experimental Evaluation of Classical Homogeneous Nucleation Theory

4 Experimental Evaluation of Classical Homogeneous Nucleation Theory 

The experimental techniques outlined above have been used to study the nucleation of a wide range of substances (Heist and He 1994). The agreement between different methods is generally good for most substances, although there exist notable exceptions. 

Two effects are observed in homogeneous nucleation experiments for all substances. First, the nucleation rate is always a steep function of saturation ratio S. The second feature common to all systems is that the critical saturation ratio Sc decreases as T increases, and J increases as T increases at constant S. Also, critical nuclei become smaller as 5 increases and as T increases. 

FIGURE 10.7 Nucleation rates measured in supersaturated n-butanol vapor as a function of saturation ratio for various temperatures ranging from 225 to 265 K (Viisanen and Strey, 1994). Different symbols indicate different carrier gases at 240 K. Predictions of classical nucleation theory are shown by the lines. (Reprinted with permission from Viisanen, Y. and Strey, R., V. M. Homogeneous Nucleation Rates for n-Butanol, J. Chem. Phys. 101. Copyright 1994 American Institute of Physics.) 

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