Experiments on the sticking probability for water molecules during condensation of water vapor in air

Abstract

Condensational particle growth has been investigated by many authors using various measuring principles and observation techniques (see (i) for review). While diffusion chambers are restricted to the study of slow growth processes, expansion chambers have been applied to investigate fast particle growth at high saturation ratios. Comparison of experimental and theoretical growth rates allows a determination of the sticking probability for the condensing molecules. For the case of water molecules considerable disagreement can be observed in the literature different authors reporting values for the sticking probability varying over a range from about 0.01 to i. This conflict has not yet been resolved. In the present paper we report measurements of water drop growth in air in an expansion chamber covering the entire range of saturation ratios from about 106 to 360 %. The results are compared with numerical calculations accounting for nonlinear effects and the sticking probability for water molecules is estimated.