Infrared-driven unimolecular reaction of CH3CHOO Criegee intermediates to OH radical products
Infrared-driven unimolecular reaction of CH3CHOO Criegee intermediates to OH radical products
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DOI：
10.1126/science.1257158
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发表时间：
2014-09-26
期刊：
影响因子：
56.9
通讯作者：
Lester, Marsha I.
中科院分区：
文献类型：
--
作者：
Liu, Fang;Beames, Joseph M.;Lester, Marsha I.
烯烃的臭氧分解是对流层中羟基（OH）自由基的重要非光解来源，它通过能量化的Criegee中间体进行单分子衰变产生OH自由基。在这里，我们使用红外（IR）激活冷CH3CHOO Criegee中间体驱动氢从甲基转移到末端氧，然后解离为OH自由基。在CH伸缩泛音区域结合灵敏的OH检测的CH3CHOO的状态选择性激发揭示了CH3CHOO的红外光谱，有效的势垒高度的关键氢转移步骤，和快速衰减动力学OH产品。互补理论提供了对IR泛音光谱的见解，以及振动激发，结构变化和从CH3CHOO的最小能量构型移动到氢转移反应的过渡态所需的能量。
Ozonolysis of alkenes, an important nonphotolytic source of hydroxyl (OH) radicals in the troposphere, proceeds through energized Criegee intermediates that undergo unimolecular decay to produce OH radicals. Here, we used infrared (IR) activation of cold CH3CHOO Criegee intermediates to drive hydrogen transfer from the methyl group to the terminal oxygen, followed by dissociation to OH radicals. State-selective excitation of CH3CHOO in the CH stretch overtone region combined with sensitive OH detection revealed the IR spectrum of CH3CHOO, effective barrier height for the critical hydrogen transfer step, and rapid decay dynamics to OH products. Complementary theory provides insights on the IR overtone spectrum, as well as vibrational excitations, structural changes, and energy required to move from the minimum-energy configuration of CH3CHOO to the transition state for the hydrogen transfer reaction.