Collision-Energy Dependence of the Uptake of Hydroxyl Radicals at Atmospherically Relevant Liquid Surfaces
Collision-Energy Dependence of the Uptake of Hydroxyl Radicals at Atmospherically Relevant Liquid Surfaces
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大气相关液体表面羟基自由基吸收的碰撞能量依赖性
DOI：
10.1021/acs.jpcc.7b12574
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Bianchini R
中科院分区：
文献类型：
--
作者：
Bianchini R
描述了一种新的实验方法来研究羟基自由基与液体表面的碰撞，结合OH（或在实践中，由于技术原因，OD）自由基的分子束源。这样就可以检验散射对碰撞能量的依赖性。用激光诱导荧光检测入射和散射OD分子。将代表性的支链长链烷烃角鲨烷（2,6,10,15,19,23-六亚甲基四烷）及其部分不饱和类似物角鲨烯（2,6,10,15,19,23-六亚甲基-2,6,10,14,18,22-四碳六烯）与全氟聚醚作为惰性对照液进行了比较。动力学方面的散射需要量化OD存活概率，因此它的补充，反应性粘附系数，被确定。实验框架平均动能分别为7.2和29.5 kJ mol-1；将它们与以前使用平均动能为54 kJ mol-1的OH光解源的独立测量结果进行比较。在较低的碰撞能量下，角鲨烯的生存概率显著低于角鲨烷，但随着碰撞能量的增加，生存概率显著增加。这与角鲨烯表面双键位点的负活化对羟基损失的贡献是一致的。相比之下，在角鲨烷表面的生存被发现与所检查范围内的碰撞能量大约无关。这是令人惊讶的，因为它没有反映气相OH +烷烃反应的典型正激活行为。我们认为这可能是由于在较低的碰撞能量下捕获动力学的可能性较高，从而提高了迁移到更多活性位点后的反应概率。这些结果对模拟大气气溶胶表面的OH吸收作为化学成分和温度的函数具有启示意义。
A new experimental approach to the study of collisions of hydroxyl radicals with liquid surfaces is described, incorporating a molecular-beam source of OH (or, in practice, OD, for technical reasons) radicals. This allowed the collision-energy dependence of the scattering to be examined. The incident and scattered OD molecules were detected by laser-induced fluorescence. The representative branched, long-chain alkane, squalane (2,6,10,15,19,23-hexamethyltetracosane), and its partially unsaturated analogue, squalene (2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene), were compared with perfluoropolyether as an inert reference liquid. Dynamical aspects of the scattering necessary to quantify the OD survival probability, and hence its complement, the reactive sticking coefficient, were determined. Results were obtained at average laboratory-frame kinetic energies of 7.2 and 29.5 kJ mol–1; they are compared with previous independent measurements using a photolytic source of OH with an average kinetic energy of 54 kJ mol–1. At lower collision energies, the survival probability is significantly lower on squalene than on squalane but increases significantly with collision energy. This is consistent with a negatively activated contribution to loss of hydroxyl through addition to double-bond sites at the squalene surface. In contrast, survival on squalane surface is found to be approximately independent of collision energy across the range examined. This is surprising because it does not reflect the positively activated behavior typical of gas-phase OH + alkane reactions. We suggest that this may be explained by a higher probability of trapping dynamics at lower collision energies, enhancing the probability of reaction following migration to more reactive sites. The results have implications for the modeling of OH uptake on atmospheric aerosol surfaces as a function of chemical composition and temperature.
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有机液体中 OH 自由基的非弹性散射：隔离热解吸通道。
DOI：
10.1039/c3cp51708j
发表时间：
2013
期刊：
PCCP
影响因子：
--
作者：
King KL
通讯作者：
King KL
直接气液界面动力学：O(3P) 和液态烃之间的反应。
DOI：
10.1021/jp056128q
发表时间：
2006
期刊：
The journal of physical chemistry. B
影响因子：
--
作者：
Sven P K Köhler;M. Allan;M. Costen;K. McKendrick
通讯作者：
K. McKendrick
DOI：
10.1039/ft9938903877
发表时间：
1993
期刊：
Journal of the Chemical Society, Faraday Transactions
影响因子：
--
作者：
A. Kenyon;A. J. McCaffery;C. Quintella;M. Zidan
通讯作者：
M. Zidan
质子和非质子气体与氢键和碳氢化合物液体的碰撞
影响因子：
4.4
作者：
Mary E. Saecker;G. Nathanson
通讯作者：
G. Nathanson
影响因子：
14.7
作者：
M. A. Tesa-Serrate;E. Smoll;T. Minton;K. McKendrick
通讯作者：
M. A. Tesa-Serrate;E. Smoll;T. Minton;K. McKendrick