Condensation of a supersaturated vapor. VIII. The homogeneous nucleation of n-nonane

Abstract

Homogeneous nucleation rates for n-nonane were measured as a function of supersaturation at nine temperatures (233 to 315 K) using an upward thermal diffusion cloud chamber. On each isotherm, the supersaturations were set to values which produced nucleation rates ranging from about 5×10−5 to 100 drop cm−3 s−1. The observed dependences on both temperature and supersaturation were compared to the predictions of several nucleation theories. Closest agreement was obtained with classical theory. Nonetheless, a multiplicative temperature-dependent correction that ranges from 2×10−5 at 233 K to 4×103 at 315 K was required to make classical theory agree with experiment. A comparison of our nucleation rate measurements to measurements made using two different expansion cloud chambers showed consistent deviations from classical theory.