Ice Formation via Deposition Mode Nucleation on Bare and Alcohol-Covered Graphite Surfaces

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• 作者：Xiangrui Kong ; Patrik U. Andersson ; Erik S. Thomson ; Jan B. C. Pettersson
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：April 26, 2012
• 年：2012
• 卷：116
• 期：16
• 页码：8964-8974
• 全文大小：620K
• 年卷期：v.116,no.16(April 26, 2012)
• ISSN：1932-7455

文摘

Deposition of water on aerosol particles contributes to ice cloud formation in the atmosphere with implications for the water cycle and climate on Earth. The heterogeneous ice nucleation process is influenced by physicochemical properties of the substrate, but the mechanisms remain incompletely understood. Here, we report on ice formation on bare and alcohol-covered graphite at temperatures from 175 to 213 K, probed by elastic helium and light scattering. Water has a low wettability on bare and butanol-covered graphite resulting in the growth of rough ice surfaces. In contrast, preadsorbed methanol provides hydrophilic surface sites and results in the formation of smooth crystalline ice; an effect that is pronounced also for submonolayer methanol coverages. The alcohols primarily reside at the ice surface and at the ice鈥揼raphite interface with a minor fraction being incorporated into the growing ice structures. Methanol has no observable effect on gas/solid water vapor exchange, whereas butanol acts as a transport barrier for water resulting in a reduction in ice evaporation rate at 185 K. Implications for the description of deposition mode freezing are discussed.