Mechanisms of Electron-Induced Chemistry in Molecular Ices
Mechanisms of Electron-Induced Chemistry in Molecular Ices
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DOI：
10.3390/atoms10010025
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发表时间：
2022-03-01
期刊：
影响因子：
1.8
通讯作者：
Bredehoeft, Jan Hendrik
中科院分区：
文献类型：
--
作者：
Schmidt, Fabian;Borrmann, Tobias;Bredehoeft, Jan Hendrik
电子诱导化学与电离辐射与物质相互作用时发生的许多过程有关。这包括辐射损伤，聚合物固化和纳米纤维工艺，但也包括在太空尘埃颗粒上生长的分子冰中形成复杂分子。高能辐射从这种材料中释放出大量的二次电子，其中大多数的能量低于20 eV。当这些电子附着在分子上或诱导电子激发和进一步电离时，它们有效地触发反应。本文综述了能量在0 ~ 20 eV之间的电子在由小分子（H2O，CO，CH 3OH，NH3，CH 4，C2 H4，CH 3CN，C2 H6）或其衍生物（C（2）H（5）NH（2）和（C2 H5）2 NH，CH 2 = CHCH 3）组成的二元冰层中诱导形成较大产物的反应机理。它总结了我们的方法，以确定产品和量化其数量的基础上，热解吸光谱（TDS）和电子刺激解吸（ESD）实验在超高真空（UHV）。结果的概述表明，虽然最初的电子-分子相互作用是一个非热的过程，从所得的反应性物种的产品形成往往是由随后的反应，遵循众所周知的热和自由基驱动的有机化学机制。
Electron-induced chemistry is relevant to many processes that occur when ionizing radiation interacts with matter. This includes radiation damage, curing of polymers, and nanofabrication processes but also the formation of complex molecules in molecular ices grown on dust particles in space. High-energy radiation liberates from such materials an abundance of secondary electrons of which most have energies below 20 eV. These electrons efficiently trigger reactions when they attach to molecules or induce electronic excitation and further ionization. This review focuses on the present state of insight regarding the mechanisms of reactions induced by electrons with energies between 0 and 20 eV that lead to formation of larger products in binary ice layers consisting of small molecules (H2O, CO, CH3OH, NH3, CH4, C2H4, CH3CN, C2H6) or some derivatives thereof (C(2)H(5)NH(2 )and (C2H5) 2 NH, CH2=CHCH3). It summarizes our approach to identify products and quantify their amounts based on thermal desorption spectrometry (TDS) and electron-stimulated desorption (ESD) experiments performed in ultrahigh vacuum (UHV). The overview of the results demonstrates that, although the initial electron-molecule interaction is a non-thermal process, product formation from the resulting reactive species is often governed by subsequent reactions that follow well-known thermal and radical-driven mechanisms of organic chemistry.