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 ofthe water-n-propanol system. physicall y unrealistic predictions are seen. At water-gas-phase activities above 1, the theory predicts negative molecular occupation numbers of water in the c ritical clusters. In the case of water-sulfuric acid, however, the predicti ons are realistic. A series of quantitative experiments of heterogeneous nu cleation of water-n-propanol on oxidized silver particles have been perform ed. and the results are contrasted xith the theoretical predictions.