论文标题
C2H2，C2H4和C2H6中的激进添加和H抽象反应：星际培养基中乙基和乙烯基轴承分子的网关
Radical Addition and H Abstraction Reactions in C2H2, C2H4 and C2H6: A Gateway for Ethyl and Vinyl Bearing Molecules in the Interstellar Medium
论文作者
论文摘要
最近的星际检测包括其结构中大量含有乙烯基（C2H3）和乙基（C2H5）基的分子。对于这些分子中的几个，没有明确的实验或理论证据支持它们从更简单的前体中形成。我们从封闭的壳烃（含有两个碳原子（乙烷，C2H6;乙烯，C2H4;和乙炔，C2H2））进行了系统的搜索，以确定可行的化学途径，以形成乙烯基和乙基分子的乙基粉尘颗粒顶部。我们的结果表明，H和OH自由基都是将乙炔和乙烯转化为更复杂的自由基的关键，这些自由基易于继续反应和形成星际复合物有机分子。相关反应，例如OH添加，当前速率常数超过10 $^{1} $ s $^{ - 1} $，它们可能在谷物上具有OH扩散而具有竞争力。同样，在所有情况下，乙炔和乙烯的H原子是一个非常快的过程，其速率常数高于10 $^{4} $ s $^{ - 1} $，并且通过量子隧道大大增强。氢抽象反应的相关性较小，但可能在涉及OH自由基的特定情况下发挥作用。与其他自由基NH2，CH3的反应可能对乙基和乙烯基轴承分子的化学影响较小。
Recent interstellar detections include a significant number of molecules containing vinyl (C2H3) and ethyl (C2H5) groups in their structure. For several of these molecules, there is not a clear experimental or theoretical evidence that support their formation from simpler precursors. We carried out a systematic search of viable reactions starting from closed shell hydrocarbons containing two carbon atoms (ethane, C2H6; ethylene, C2H4; and acetylene, C2H2) with the goal of determining viable chemical routes for the formation of vinyl and ethyl molecules on top of interstellar dust grains. Our results show that both H and OH radicals are key in converting acetylene and ethylene into more complex radicals that are susceptible to continue reacting and forming interstellar complex organic molecules. The relevant reactions, for example OH additions, present rate constants above 10$^{1}$ s$^{-1}$ that are likely competitive with OH diffusion on grains. Similarly, H atom addition to acetylene and ethylene is a very fast process with rate constants above 10$^{4}$ s$^{-1}$ in all cases, and greatly enhanced by quantum tunneling. Hydrogen abstraction reactions are less relevant, but may play a role in specific cases involving the OH radical. Reactions with other radicals NH2, CH3 are likely to have a much lesser impact in the chemistry of ethyl and vinyl bearing molecules.
