Deposition nucleation on mineral dust particles: a case against classical nucleation theory with the assumption of a single contact angle

Autor: M. J. Wheeler, A. K. Bertram
Jazyk: angličtina
Rok vydání: 2012
Předmět:
Zdroj: Atmospheric Chemistry and Physics, Vol 12, Iss 2, Pp 1189-1201 (2012)
Druh dokumentu: article
ISSN: 1680-7316
1680-7324
DOI: 10.5194/acp-12-1189-2012
Popis: Deposition nucleation on two mineral species, kaolinite and illite, was studied using a flow cell coupled to an optical microscope. The results show that the Sice conditions when ice first nucleated, defined as the onset Sice (Sice,onset), is a strong function of the surface area available for nucleation, varying from 100% to 125% at temperatures between 242 and 239 K. The surface area dependent data could not be described accurately using classical nucleation theory and the assumption of a single contact angle (defined here as the single-α model). These results suggest that caution should be applied when using contact angles determined from Sice,onset data and the single-α model. In contrast to the single-α model, the active site model, the deterministic model, and a model with a distribution of contact angles fit the data within experimental uncertainties. Parameters from the fits to the data are presented.
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