Molecular simulations reveal that heterogeneous ice nucleation occurs at higher temperatures in water under capillary tension
<p>Heterogeneous ice nucleation is thought to be the primary pathway for the formation of ice in mixed-phase clouds, with the number of active ice-nucleating particles (INPs) increasing rapidly with decreasing temperature. Here, molecular-dynamics simulations of heterogeneous ice nucleation de...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-09-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/23/10625/2023/acp-23-10625-2023.pdf |
| _version_ | 1797674005989163008 |
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| author | E. Rosky W. Cantrell T. Li I. Nakamura R. A. Shaw |
| author_facet | E. Rosky W. Cantrell T. Li I. Nakamura R. A. Shaw |
| author_sort | E. Rosky |
| collection | DOAJ |
| description | <p>Heterogeneous ice nucleation is thought to be the primary pathway for the formation of ice in mixed-phase clouds, with the number of active ice-nucleating particles (INPs) increasing rapidly with decreasing temperature. Here, molecular-dynamics simulations of heterogeneous ice nucleation demonstrate that the ice nucleation rate is also sensitive to pressure and that negative pressure within supercooled water shifts freezing temperatures to higher temperatures. Negative pressure, or tension, occurs naturally in water capillary bridges and pores and can also result from water agitation. Capillary bridge simulations presented in this study confirm that negative Laplace pressure within the water increases heterogeneous-freezing temperatures. The increase in freezing temperatures with negative pressure is approximately linear within the atmospherically relevant range of 1 to <span class="inline-formula">−</span>1000 atm. An equation describing the slope depends on the latent heat of freezing and the molar volume difference between liquid water and ice. Results indicate that negative pressures of <span class="inline-formula">−</span>500 atm, which correspond to nanometer-scale water surface curvatures, lead to a roughly 4 K increase in heterogeneous-freezing temperatures. In mixed-phase clouds, this would result in an increase of approximately 1 order of magnitude in active INP concentrations. The findings presented here indicate that any process leading to negative pressure in supercooled water may play a role in ice formation, consistent with experimental evidence of enhanced ice nucleation due to surface geometry or mechanical agitation of water droplets. This points towards the potential for dynamic processes such as contact nucleation and droplet collision or breakup to increase ice nucleation rates through pressure perturbations.</p> |
| first_indexed | 2024-03-11T21:52:48Z |
| format | Article |
| id | doaj.art-a585ddad7b8c411dbb41662212ca0161 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-03-11T21:52:48Z |
| publishDate | 2023-09-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-a585ddad7b8c411dbb41662212ca01612023-09-26T07:19:10ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242023-09-0123106251064210.5194/acp-23-10625-2023Molecular simulations reveal that heterogeneous ice nucleation occurs at higher temperatures in water under capillary tensionE. Rosky0W. Cantrell1T. Li2I. Nakamura3R. A. Shaw4Department of Physics, Michigan Technological University, Houghton, MI, USADepartment of Physics, Michigan Technological University, Houghton, MI, USADepartment of Civil & Environmental Engineering, George Washington University, Washington, DC, USADepartment of Physics, Michigan Technological University, Houghton, MI, USADepartment of Physics, Michigan Technological University, Houghton, MI, USA<p>Heterogeneous ice nucleation is thought to be the primary pathway for the formation of ice in mixed-phase clouds, with the number of active ice-nucleating particles (INPs) increasing rapidly with decreasing temperature. Here, molecular-dynamics simulations of heterogeneous ice nucleation demonstrate that the ice nucleation rate is also sensitive to pressure and that negative pressure within supercooled water shifts freezing temperatures to higher temperatures. Negative pressure, or tension, occurs naturally in water capillary bridges and pores and can also result from water agitation. Capillary bridge simulations presented in this study confirm that negative Laplace pressure within the water increases heterogeneous-freezing temperatures. The increase in freezing temperatures with negative pressure is approximately linear within the atmospherically relevant range of 1 to <span class="inline-formula">−</span>1000 atm. An equation describing the slope depends on the latent heat of freezing and the molar volume difference between liquid water and ice. Results indicate that negative pressures of <span class="inline-formula">−</span>500 atm, which correspond to nanometer-scale water surface curvatures, lead to a roughly 4 K increase in heterogeneous-freezing temperatures. In mixed-phase clouds, this would result in an increase of approximately 1 order of magnitude in active INP concentrations. The findings presented here indicate that any process leading to negative pressure in supercooled water may play a role in ice formation, consistent with experimental evidence of enhanced ice nucleation due to surface geometry or mechanical agitation of water droplets. This points towards the potential for dynamic processes such as contact nucleation and droplet collision or breakup to increase ice nucleation rates through pressure perturbations.</p>https://acp.copernicus.org/articles/23/10625/2023/acp-23-10625-2023.pdf |
| spellingShingle | E. Rosky W. Cantrell T. Li I. Nakamura R. A. Shaw Molecular simulations reveal that heterogeneous ice nucleation occurs at higher temperatures in water under capillary tension Atmospheric Chemistry and Physics |
| title | Molecular simulations reveal that heterogeneous ice nucleation occurs at higher temperatures in water under capillary tension |
| title_full | Molecular simulations reveal that heterogeneous ice nucleation occurs at higher temperatures in water under capillary tension |
| title_fullStr | Molecular simulations reveal that heterogeneous ice nucleation occurs at higher temperatures in water under capillary tension |
| title_full_unstemmed | Molecular simulations reveal that heterogeneous ice nucleation occurs at higher temperatures in water under capillary tension |
| title_short | Molecular simulations reveal that heterogeneous ice nucleation occurs at higher temperatures in water under capillary tension |
| title_sort | molecular simulations reveal that heterogeneous ice nucleation occurs at higher temperatures in water under capillary tension |
| url | https://acp.copernicus.org/articles/23/10625/2023/acp-23-10625-2023.pdf |
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