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Phase State, Surface Tension, Water Activity, and Accommodation Coefficient of Water–Organic Clusters Near the Critical Size for Atmospheric New Particle Formation

[Image: see text] Interactions between water and organic molecules in sub-4 nm clusters play a significant role in the formation and growth of secondary organic aerosol (SOA) particles. However, a complete understanding of the relevant water microphysics has not yet been achieved due to challenges i...

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Autores principales: Li, Xiaohan, Bourg, Ian C.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2023
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10483925/
https://www.ncbi.nlm.nih.gov/pubmed/37607019
http://dx.doi.org/10.1021/acs.est.2c09627
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author Li, Xiaohan
Bourg, Ian C.
author_facet Li, Xiaohan
Bourg, Ian C.
author_sort Li, Xiaohan
collection PubMed
description [Image: see text] Interactions between water and organic molecules in sub-4 nm clusters play a significant role in the formation and growth of secondary organic aerosol (SOA) particles. However, a complete understanding of the relevant water microphysics has not yet been achieved due to challenges in the experimental characterization of soft nuclei. Here, we use molecular dynamics simulations to study the phase-mixing states, surface tension, water activity, and water accommodation coefficient of organic–water clusters representative of freshly nucleated SOA particles. Our results reveal large deviations from the behavior expected based on continuum theories. In particular, the phase-mixing state has a strong dependence on cluster size; surface tension displays a minimum at a specific organic–water mass ratio (m(org)/m(w) ∼ 4.5 in this study) corresponding to a minimum inhibition of droplet nucleation associated with the Kelvin effect; and the water accommodation coefficient increases by a factor of 2 with nanocluster hygroscopic growth, in agreement with recent experimental studies. Overall, our results yield parametric relations for water microphysical properties in sub-4 nm clusters and provide insight into the role of water in the initial stages of SOA nucleation and growth.
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spelling pubmed-104839252023-09-08 Phase State, Surface Tension, Water Activity, and Accommodation Coefficient of Water–Organic Clusters Near the Critical Size for Atmospheric New Particle Formation Li, Xiaohan Bourg, Ian C. Environ Sci Technol [Image: see text] Interactions between water and organic molecules in sub-4 nm clusters play a significant role in the formation and growth of secondary organic aerosol (SOA) particles. However, a complete understanding of the relevant water microphysics has not yet been achieved due to challenges in the experimental characterization of soft nuclei. Here, we use molecular dynamics simulations to study the phase-mixing states, surface tension, water activity, and water accommodation coefficient of organic–water clusters representative of freshly nucleated SOA particles. Our results reveal large deviations from the behavior expected based on continuum theories. In particular, the phase-mixing state has a strong dependence on cluster size; surface tension displays a minimum at a specific organic–water mass ratio (m(org)/m(w) ∼ 4.5 in this study) corresponding to a minimum inhibition of droplet nucleation associated with the Kelvin effect; and the water accommodation coefficient increases by a factor of 2 with nanocluster hygroscopic growth, in agreement with recent experimental studies. Overall, our results yield parametric relations for water microphysical properties in sub-4 nm clusters and provide insight into the role of water in the initial stages of SOA nucleation and growth. American Chemical Society 2023-08-22 /pmc/articles/PMC10483925/ /pubmed/37607019 http://dx.doi.org/10.1021/acs.est.2c09627 Text en © 2023 American Chemical Society https://creativecommons.org/licenses/by-nc-nd/4.0/Permits non-commercial access and re-use, provided that author attribution and integrity are maintained; but does not permit creation of adaptations or other derivative works (https://creativecommons.org/licenses/by-nc-nd/4.0/).
spellingShingle Li, Xiaohan
Bourg, Ian C.
Phase State, Surface Tension, Water Activity, and Accommodation Coefficient of Water–Organic Clusters Near the Critical Size for Atmospheric New Particle Formation
title Phase State, Surface Tension, Water Activity, and Accommodation Coefficient of Water–Organic Clusters Near the Critical Size for Atmospheric New Particle Formation
title_full Phase State, Surface Tension, Water Activity, and Accommodation Coefficient of Water–Organic Clusters Near the Critical Size for Atmospheric New Particle Formation
title_fullStr Phase State, Surface Tension, Water Activity, and Accommodation Coefficient of Water–Organic Clusters Near the Critical Size for Atmospheric New Particle Formation
title_full_unstemmed Phase State, Surface Tension, Water Activity, and Accommodation Coefficient of Water–Organic Clusters Near the Critical Size for Atmospheric New Particle Formation
title_short Phase State, Surface Tension, Water Activity, and Accommodation Coefficient of Water–Organic Clusters Near the Critical Size for Atmospheric New Particle Formation
title_sort phase state, surface tension, water activity, and accommodation coefficient of water–organic clusters near the critical size for atmospheric new particle formation
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10483925/
https://www.ncbi.nlm.nih.gov/pubmed/37607019
http://dx.doi.org/10.1021/acs.est.2c09627
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