Onel Lavinia, Blitz Mark, Seakins Paul, Heard Dwayne, Stone Daniel
J Phys Chem A. 2020 Aug 6;124(31):6287-6293. doi: 10.1021/acs.jpca.0c04422. Epub 2020 Jul 22.
The kinetics of the gas phase reactions of the Criegee intermediate CHOO with O and IO have been studied at 296 K and 300 Torr through simultaneous measurements of CHOO, the CHOO precursor (CHI), O, and IO using flash photolysis of CHI/O/O/N mixtures at 248 nm coupled to time-resolved broadband UV absorption spectroscopy. Experiments were performed under pseudo-first-order conditions with respect to O, with the rate coefficients for reactions of CHOO with O and IO obtained by fitting to the observed decays of CHOO using a model constrained to the measured concentrations of IO. Fits were performed globally, with the ratio between the initial concentration of O and the average concentration of IO varying in the range 30-700, and gave = (3.6 ± 0.8) × 10 cm molecule s and = (7.6 ± 1.4) × 10 cm molecule s (where the errors are at the 2σ level). The magnitude of has a significant effect on the steady state concentration of CHOO in chamber studies. Atmospheric implications of the results are discussed.
通过在248nm下对CHI/O₂/O₃/N₂混合物进行闪光光解并结合时间分辨宽带紫外吸收光谱，同时测量CHOO、CHOO前体（CHI）、O₂和IO，研究了Criegee中间体CHOO与O₂和IO在296K和300Torr下的气相反应动力学。实验在O₂的准一级条件下进行，通过使用一个受测量的IO浓度约束的模型拟合观察到的CHOO衰变，获得了CHOO与O₂和IO反应的速率系数。进行全局拟合，O₂的初始浓度与IO的平均浓度之比在30 - 700范围内变化，得到k₁ = (3.6 ± 0.8) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹和k₂ = (7.6 ± 1.4) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹（其中误差为2σ水平）。k₁的大小对腔室研究中CHOO的稳态浓度有显著影响。讨论了结果对大气的影响。
