The importance of OH radical-neutral low temperature tunnelling reactions in interstellar clouds using a new model
The importance of OH radical-neutral low temperature tunnelling reactions in interstellar clouds using a new model
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DOI：
10.1080/00268976.2015.1021729
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发表时间：
2015-08-18
影响因子：
1.7
通讯作者：
Heard, D. E.
中科院分区：
文献类型：
--
作者：
Acharyya, K.;Herbst, E.;Heard, D. E.
最近使用脉冲拉瓦尔喷嘴装置的实验室实验已经表明，中性分子和自由基OH之间的反应可以在低温下有效地发生，尽管活化能障碍，如果在入口通道中存在氢键络合物，其允许系统在障碍下有效地隧穿。由于OH是星际介质中的主要自由基，这类反应在星际云的气相化学中可能很重要。使用一个新的气体-颗粒化学网络，气相反应和尘埃颗粒表面的反应，我们研究了在10，50和100 K的致密星际云中OH-中性反应的作用。我们确定，这些反应中至少有一个可以是显着的，特别是在最低温度下研究，其中的速率常数是大的。特别是发现，CH 3OH和OH之间的反应提供了一个有效的和明确的气相路线生产的气态甲氧基自由基（CH 3 O），这已被最近检测到在寒冷，密集的interstsellar云。本课程探讨了其他反应的作用。
Recent laboratory experiments using a pulsed Laval nozzle apparatus have shown that reactions between a neutral molecule and the radical OH can occur efficiently at low temperatures despite activation energy barriers if there is a hydrogen-bonded complex in the entrance channel which allows the system to tunnel efficiently under the barrier. Since OH is a major radical in the interstellar medium, this class of reactions may well be important in the chemistry that occurs in the gas phase of interstellar clouds. Using a new gas-grain chemical network with both gas-phase reactions and reactions on the surfaces of dust particles, we studied the role of OH-neutral reactions in dense interstellar clouds at 10, 50, and 100 K. We determined that at least one of these reactions can be significant, especially at the lowest temperatures studied, where the rate constants are large. It was found in particular that the reaction between CH3OH and OH provides an effective and unambiguous gas-phase route to the production of the gaseous methoxy radical (CH3O), which has been recently detected in cold, dense interstsellar clouds. The role of other reactions in this class is explored.