Repairing the first nucleation theorem: Precritical cluster losses

Abstract. The SAWNUC microphysical aerosol nucleation model is used to study the effect of reactor walls on the interpretation of nucleation experiments with respect to nucleation theory. This work shows that loss processes, such as wall losses, influence the interpretation of nucleation experiments, especially at low growth rates and short lifetime of freshly nucleated particles. In these cases the power dependency of the formation rates, determined at a certain particle size, with respect to H2SO4 does not correspond to the approximate number of H2SO4 molecules in the critical cluster as expected by the first nucleation theorem. Observed ∂log(J)/∂log([H2SO4]) therefore can vary widely for identical nucleation conditions but different sink terms.

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Third application of the nucleation theorem

Nucleation ◽

10.1016/b978-075064682-6/50029-9 ◽

2000 ◽

pp. 410-412

Author(s):

Dimo Kashchiev

Keyword(s):

Nucleation Theorem

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Critical Size of Secondary Nuclei Determined via Nucleation Theorem Reveals Selective Nucleation in Three-Component Co-Crystals

Entropy ◽

10.3390/e21111032 ◽

2019 ◽

Vol 21 (11) ◽

pp. 1032 ◽

Cited By ~ 1

Author(s):

Yang Gao ◽

Baohua Guo ◽

Jun Xu

Keyword(s):

Growth Rate ◽

Crystal Growth ◽

Ethylene Oxide ◽

Inclusion Compound ◽

Critical Size ◽

Lateral Spreading ◽

Crystal Growth Rate ◽

Poly Ethylene Oxide ◽

Poly Ethylene ◽

Nucleation Theorem

The critical size of the secondary nuclei plays an important role in determining the crystal growth rate. In the past, the Nucleation Theorem has been applied to determine the number of molecules in the critical nuclei of a single-component crystal via variation of the crystal growth rate with dilution by the non-crystallizable component. In this work, we extend the method to the three-component co-crystal poly (ethylene oxide)/urea/thiourea inclusion compound. The theoretical crystal growth kinetics were deduced and the dependence of the radial growth rate of the inclusion compound spherulites on the mass fraction of urea in urea/thiourea was measured. The results reveal that the secondary nuclei of the poly (ethylene oxide)/urea/thiourea inclusion compound consist mainly of ethylene oxide repeating units and urea molecules. We propose that only urea molecules and ethylene oxide repeating units are selected to form the secondary nuclei while co-crystallization of the three components happens at the lateral spreading stage. As a result, the composition of the critical secondary nuclei is different from that of the bulk inclusion compound crystals. The work is expected to deepen our understanding of the nucleation of multi-component co-crystals.

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