Heterogeneous multicomponent nucleation theorems for the analysis of nanoclusters.
In this paper we present a new form of the nucleation theorems applicable to heterogeneous nucleation. These heterogeneous nucleation theorems allow, for the first time, direct determination of properties of nanoclusters formed on pre-existing particles from measured heterogeneous nucleation probabilities. The theorems can be used to analyze the size (first theorem) and the energetics (second theorem) of heterogeneous clusters independent of any specific nucleation model. We apply the first theorem to the study of small water and n-propanol clusters formed at the surface of 8 nm silver particles. According to the experiments the size of the two-component critical clusters is found to be below 90 molecules, and only less than 20 molecules for pure water, less than 300 molecules for pure n-propanol. These values are drastically smaller than the ones predicted by the classical nucleation theory, which clearly indicates that the nucleating clusters are too small to be quantitatively described using a macroscopic theory.
Vehkamäki
Hanna
H
Department of Physical Sciences, P.O. Box 64, University of Helsinki, 00014 Helsinki, Finland. hanna.vehkamaki@helsinki.fi
Määttänen
Anni
A
Lauri
Antti
A
Kulmala
Markku
M
Winkler
Paul
P
Vrtala
Aron
A
Wagner
Paul E
PE