发表机构
Leiden University; Xinjiang Astronomical Observatory, Chinese Academy of Sciences; Aarhus University（莱顿大学; 中国科学院新疆天文台; 奥胡斯大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过紫外辐照纯乙炔冰实验，发现可生成含多达13个碳原子的挥发性及难熔烃，表明星际条件下乙炔固态反应能产生显著分子复杂性，对未识别红外发射带具有潜在意义。
AI 中文摘要
乙炔（C$_2$H$_2$）在恒星形成区、年轻恒星天体和太阳系中普遍存在。实验室和理论研究已通过紫外或宇宙射线驱动的化学将该最简单的炔烃与挥发性碳氢化合物和多环芳烃（PAHs）联系起来，但仍不清楚难熔物质是否能通过尘埃颗粒上C$_2$H$_2$的固态反应有效形成。我们实验研究了纯C$_2$H$_2$冰经紫外辐照诱导的化学复杂性，并表征了挥发性和非挥发性光产物。实验在MATRI$^2$CES装置上于15 K超高真空条件下进行，使用7.2--10.2 eV光子。经紫外处理的冰通过激光解吸后电离反射式飞行时间质谱（LDPI ReTOF-MS）结合脉冲离子偏转（PID）进行原位监测。挥发性和难熔产物分别在15 K和300 K下原位测量。在通量$3 \times 10^{17}$光子cm$^{-2}$（相当于稠密云中约$10^6$年）后，形成了含多达13个碳原子的大饱和及不饱和碳氢化合物。挥发性产物升华后，300 K残留物显示出丰富且独特的质谱，与含有共轭三键（-C$\equiv$C-）和双键（-C=C-）的难熔物质一致。这些结果表明，在天文相关条件下，纯C$_2$H$_2$冰的紫外处理可产生显著的分子复杂性和难熔碳氢化合物，对未识别红外发射带可能具有意义。
英文摘要
Acetylene (C$_2$H$_2$) is commonly observed in star-forming regions, young stellar objects, and the Solar System. Laboratory and theoretical studies have linked this simplest alkyne to volatile hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) through UV- or cosmic-ray-driven chemistry, but it remains unclear whether refractory material can efficiently form through solid-state reactions of C$_2$H$_2$ on dust grains. We experimentally investigate the chemical complexity induced by UV irradiation of pure C$_2$H$_2$ ice and characterize both volatile and nonvolatile photoproducts. Experiments were performed with MATRI$^2$CES under ultra-high-vacuum conditions at 15 K using 7.2--10.2 eV photons. UV-processed ices were monitored in situ by laser desorption post-ionization reflection time-of-flight mass spectrometry (LDPI ReTOF-MS) combined with pulsed ion deflection (PID). Volatile and refractory products were measured in situ at 15 and 300 K, respectively. After a fluence of $3 \times 10^{17}$ photons cm$^{-2}$, corresponding to about $10^6$ years in dense clouds, large saturated and unsaturated hydrocarbons containing up to 13 carbon atoms are formed. After sublimation of the volatile products, the 300 K residue shows a rich and distinct mass spectrum consistent with refractory material containing conjugated triple (-C$\equiv$C-) and double (-C=C-) bonds. These results demonstrate that UV processing of pure C$_2$H$_2$ ice can produce substantial molecular complexity and refractory hydrocarbons under astronomically relevant conditions, with possible implications for unidentified infrared emission bands.
Comments25 pages, 9 figures
Journal refAstronomy & Astrophysics, 705, A229 (2026)
DOI：10.1051/0004-6361/202556672
