Zhao Long, Lu Wenchao, Ahmed Musahid, Zagidullin Marsel V, Azyazov Valeriy N, Morozov Alexander N, Mebel Alexander M, Kaiser Ralf I
Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Sci Adv. 2021 May 21;7(21). doi: 10.1126/sciadv.abf0360. Print 2021 May.
Polycyclic aromatic hydrocarbons (PAHs) have been invoked in fundamental molecular mass growth processes in our galaxy. We provide compelling evidence of the formation of the very first ringed aromatic and building block of PAHs-benzene-via the self-recombination of two resonantly stabilized propargyl (CH) radicals in dilute environments using isomer-selective synchrotron-based mass spectrometry coupled to theoretical calculations. Along with benzene, three other structural isomers (1,5-hexadiyne, fulvene, and 2-ethynyl-1,3-butadiene) and -benzyne are detected, and their branching ratios are quantified experimentally and verified with the aid of computational fluid dynamics and kinetic simulations. These results uncover molecular growth pathways not only in interstellar, circumstellar, and solar systems environments but also in combustion systems, which help us gain a better understanding of the hydrocarbon chemistry of our universe.
多环芳烃（PAHs）被认为参与了我们星系中基本的分子质量增长过程。我们利用基于同步加速器的异构体选择性质谱联用理论计算，提供了令人信服的证据，证明在稀薄环境中，两个共振稳定的炔丙基（CH）自由基通过自重组形成了首个环状芳烃以及PAHs的构建单元——苯。除了苯，还检测到了其他三种结构异构体（1,5-己二炔、富烯和2-乙炔基-1,3-丁二烯）以及苯炔，并通过计算流体动力学和动力学模拟对它们的分支比进行了实验定量和验证。这些结果揭示了不仅在星际、星周和太阳系环境中，而且在燃烧系统中的分子生长途径，这有助于我们更好地理解宇宙中的烃类化学。
