Unraveling the "pressure effect" in nucleation.
The influence of the pressure of a chemically inert carrier gas on the nucleation rate is one of the biggest puzzles in the research of gas-liquid nucleation. Experiments can show a positive effect, a negative effect, or no effect at all. The same experiment may show both trends for the same substance depending on temperature, or for different substances at the same temperature. We show how this ambiguous effect naturally arises from the competition of two contributions: nonisothermal effects and pressure-volume work. Our model clarifies seemingly contradictory experimental results and quantifies the variation of the nucleation ability of a substance in the presence of an ambient gas. Our findings are corroborated by molecular dynamics simulations and might have important implications since nucleation in experiments, technical applications, and nature practically always occurs in the presence of an ambient gas.
Wedekind
Jan
J
Departament de Física Fonamental, Universitat de Barcelona, Martí i Franquès 1, Barcelona, Spain. janw@ffn.ub.es
Hyvärinen
Antti-Pekka
AP
Brus
David
D
Reguera
David
D