Adsorption of organic molecules may explain growth of newly nucleated clusters and new particle formation

Jian Wang, Anthony S. Wexler

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

New particle formation consists of formation of thermodynamically stable clusters from trace gas molecules (homogeneous nucleation) followed by growth of these clusters to a detectable size. Because of the large coagulation rate of clusters smaller than 3 nm with the preexisting aerosol population, for new particle formation to take place, these clusters need to grow sufficiently fast to escape removal by coagulation. Previous studies have indicated that condensation of low-volatility organic vapor may play an important role in the initial growth of the clusters. However, due to the relatively high vapor pressure and partial molar volume of even highly oxidized organic compounds, the strong Kelvin effect may prevent typical ambient organics from condensing on these small clusters. Earlier studies did not consider that adsorption of organic molecules on the cluster surface, due to the intermolecular forces between the organic molecule and cluster, may occur and substantially alter the growth process under sub-saturated conditions. Using the Brunauer-Emmett-Teller (BET) isotherm, we show that the adsorption of organic molecules onto the surface of clusters may significantly reduce the saturation ratio required for condensation of organics to occur, and therefore may provide a physico-chemical explanation for the enhanced initial growth by condensation of organics despite the strong Kelvin effect.

Original languageEnglish (US)
Title of host publicationAIP Conference Proceedings
Pages258-261
Number of pages4
Volume1527
DOIs
StatePublished - 2013
Event19th International Conference on Nucleation and Atmospheric Aerosols, ICNAA 2013 - Fort Collins, CO, United States
Duration: Jun 23 2013Jun 28 2013

Other

Other19th International Conference on Nucleation and Atmospheric Aerosols, ICNAA 2013
CountryUnited States
CityFort Collins, CO
Period6/23/136/28/13

Keywords

  • Adsorption
  • Kelvin effect
  • New particle formation

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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