AI 中文总结
该研究探究富氮冰中丙腈经40 MeV⁴⁰Ar⁹⁺离子辐照的分解过程，明确其可形成腈类、异腈类等产物，为天体环境中分子复杂性形成提供了新途径。
AI 中文摘要
背景：腈类是致密云、恒星形成区及富氮冰环境中关键的含氮有机分子，理解其在高能辐照下的稳定性与化学演化，对探究天体冰中复杂有机物种的形成至关重要。目的：研究富氮冰基质中丙腈（CH₃CH₂CN，下称PCN）的辐照分解过程，评估由快重离子诱导形成的腈类、异腈类、烃类及其他含氮产物。方法：在10 K下沉积PCN:N₂分子比约1:10的冰混合物，用40 MeV的⁴⁰Ar⁹⁺离子辐照，注量达1×10¹³ ions cm⁻²；通过傅里叶变换红外光谱原位监测化学演化，从所选红外谱带的注量依赖性推导分解与形成截面及辐射化学产率。结果：离子辐照可有效分解PCN，产生丰富的子产物，包括腈类与异腈类（如HCN、HCNN、HC₃N、CH₃CN、CH₃C₃N、CH₃CHCNH、CH₂CHCN、NCCN/C₂N₂、CN、C₂N）、含氮物种（如CH₂NH、CH₃NH₂、CH₃N₃、N₃⁻）及烃类（如CH₄、C₂H₂、C₂H₄、C₂H₆、C₄H₄）；推导的截面表明，含CN碎片与烃类是形成效率最高的产物之一，说明CN基团可高效保留，且发生了广泛的碳链重组。结论：PCN在富氮冰中的高能辐照过程，为致密星际云、原恒星环境及太阳系外层富氮表面相关条件下的分子复杂性形成提供了有效途径。
英文摘要
Context. Nitriles are key nitrogen-bearing organic molecules in dense clouds, star-forming regions, and nitrogen-rich icy environments. Understanding their stability and chemical evolution under energetic processing is essential for understanding the formation of complex organic species in astrophysical ices. Aims. We investigate the radiolytic processing of propionitrile (CH3CH2CN, hereafter referred to as PCN) in a nitrogen-rich ice matrix and evaluate the formation of nitriles, isonitriles, hydrocarbons, and other nitrogen-bearing products induced by swift heavy ions. Methods. A PCN:N2 ice mixture with an approximate molecular ratio of 1:10 was deposited at 10 K and irradiated with 40 MeV 40Ar9+ ions up to a fluence of 1 x 1013 ions cm-2. The chemical evolution was monitored in situ by Fourier-transform infrared spectroscopy. Destruction and formation cross sections, as well as radiation chemical yields, were derived from the fluence dependence of selected infrared bands. Results. Ion irradiation efficiently destroys PCN and produces a rich inventory of daughter species. The products include: nitriles and isonitriles such as HCN, HCNN, HC3N, CH3CN, CH3C3N, CH3CHCNH, CH2CHCN, NCCN/C2N2, CN, and C2N; nitrogen-bearing species such as CH2NH, CH3NH2, CH3N3, and N3- ; and hydrocarbons, including CH4, C2H2, C2H4, C2H6, and C4H4. The derived cross sections indicate that CN-bearing fragments and hydrocarbons are among the most efficiently formed products, demonstrating that the CN group is efficiently preserved and that extensive carbon-chain reorganization also occurs. Conclusions. The results demonstrate that the energetic processing of PCN in N2-rich ices provides an efficient pathway to molecular complexity under conditions relevant to dense interstellar clouds, protostellar environments, and nitrogen-rich outer Solar System surfaces.
Comments11 pages, 6 figures, 2 tables, accepted for publication in Astronomy & Astrophysics
