Strong Negative Temperature Dependence of the Simplest Criegee Intermediate CH2OO Reaction with Water Dimer

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• 作者：Mica C. Smith ; Chun-Hung Chang ; Wen Chao ; Liang-Chun Lin ; Kaito Takahashi ; Kristie A. Boering ; Jim Jr-Min Lin
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2015
• 出版时间：July 16, 2015
• 年：2015
• 卷：6
• 期：14
• 页码：2708-2713
• 全文大小：347K
• ISSN：1948-7185

文摘

The kinetics of the reaction of CH₂OO with water vapor was measured directly with UV absorption at temperatures from 283 to 324 K. The observed CH₂OO decay rate is second order with respect to the H₂O concentration, indicating water dimer participates in the reaction. The rate coefficient of the CH₂OO reaction with water dimer can be described by an Arrhenius expression k(T) = A exp(鈭?i>E_a/RT) with an activation energy of 鈭?.1 卤 0.6 kcal mol^鈥? and k(298 K) = (7.4 卤 0.6) 脳 10^鈥?2 cm³ s^鈥?. Theoretical calculations yield a large negative temperature dependence consistent with the experimental results. The temperature dependence increases the effective loss rate for CH₂OO by a factor of 鈭?.5 at 278 K and decreases by a factor of 鈭? at 313 K relative to 298 K, suggesting that temperature is important for determining the impact of Criegee intermediate reactions with water in the atmosphere.