Experiments on the temperature dependence of heterogeneous nucleation on nanometer-sized NaCl and Ag particles

Particular emphasis is placed on the temperature dependence of this process from -11 to + 14 degrees C. Aerosols are generated in a tube furnace and electrostatically classified at mean geometric mobility equivalent diameters between 3.6 and 11 nm.

Activation probabilities are measured by means of expansion chamber experiments, and onset n-propanol saturation ratios are subsequently determined. The experiments with Ag particles do not produce any unexpected results. The results for NaCl particles, however, show a temperature trend of the onset saturation ratios that is opposite to that predicted by classical nucleation theory.