Abstract
Upward and downward thermal diffusion cloud chambers were used to measure the critical supersaturations of dioctylphthalate (DOP) [1, 2-benzenedicarboxylic acid (bis-2-ethyl hexyl ester)] that were required for a rate of homogeneous nucleation of about 5 drops cm−3s−1. The results were compared with the predictions of the classical (Volmer-Becker-Döring-Zeldovitch) theory and the Lothe-Pound theory of homogeneous nucleation. At 293° K the classical theory overestimates the experiment by a factor of about 12 and Lothe-Pound theory underestimates it by a factor of about 0.3.