Strange Predictions by Binary Heterogeneous Nucleation Theory Compared with a Quantitative Experiment

Binary heterogeneous nucleation of water− n -propanol and water−sulfuric acid mixtures has been investigated. The classical thermodynamically consistent theory has been used. In the case of the water− n -propanol system, physically unrealistic predictions are seen. At water−gas-phase activities above 1, the theory predicts negative molecular occupation numbers of water in the critical clusters. In the case of water−sulfuric acid, however, the predictions are realistic. A series of quantitative experiments of heterogeneous nucleation of water− n -propanol on oxidized silver particles have been performed, and the results are contrasted with the theoretical predictions.