Raman Thermometry Measurements of Free Evaporation from Liquid Water Droplets

详细信息    查看全文

• 作者：Jared D. Smith ; Christopher D. Cappa ; Walter S. Drisdell ; Ronald C. Cohen ; Richard J. Saykally
• 刊名：Journal of the American Chemical Society
• 出版年：2006
• 出版时间：October 4, 2006
• 年：2006
• 卷：128
• 期：39
• 页码：12892 - 12898
• 全文大小：221K
• 年卷期：v.128,no.39(October 4, 2006)
• ISSN：1520-5126

文摘

Recent theoretical and experimental studies of evaporation have suggested that on average,molecules in the higher-energy tail of the Boltzmann distribution are more readily transferred into the vaporduring evaporation. To test these conclusions, the evaporative cooling rates of a droplet train of liquidwater injected into vacuum have been studied via Raman thermometry. The resulting cooling rates are fitto an evaporative cooling model based on Knudsen's maximum rate of evaporation, in which we explicitlyaccount for surface cooling. We have determined that the value of the evaporation coefficient (_e) of liquidwater is 0.62 ± 0.09, confirming that a rate-limiting barrier impedes the evaporation rate. Such insight willfacilitate the formulation of a microscopic mechanism for the evaporation of liquid water.