多环芳烃的实验室光化学：电离与碎片化
LABORATORY PHOTO-CHEMISTRY OF PAHS: IONIZATION VERSUS FRAGMENTATION.
作者信息
Zhen Junfeng, Castellanos Pablo, Paardekooper Daniel M, Ligterink Niels, Linnartz Harold, Nahon Laurent, Joblin Christine, Tielens Alexander G G M
机构信息
Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands ; Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands ; Universitè de Toulouse, UPS-OMP, IRAP, Toulouse, France ; CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France.
Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands ; Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, P.O. Box 9513, 2300 RA Leiden, The Netherlands.
出版信息
Astrophys J Lett. 2015 May 1;804(1). doi: 10.1088/2041-8205/804/1/L7.
Interstellar Polycyclic Aromatic Hydrocarbons (PAH) are expected to be strongly processed by Vacuum Ultra-Violet (VUV) photons. Here, we report experimental studies on the ionization and fragmentation of coronene (CH), ovalene (CH) and hexa-peri-hexabenzocoronene (HBC; CH) cations by exposure to synchrotron radiation in the range of 8-40 eV. The results show that for small PAH cations such as coronene, fragmentation (H-loss) is more important than ionization. However, as the size increases, ionization becomes more and more important and for the HBC cation, ionization dominates. These results are discussed and it is concluded that, for large PAHs, fragmentation only becomes important when the photon energy has reached the highest ionization potential accessible. This implies that PAHs are even more photo-stable than previously thought. The implications of this experimental study for the photo-chemical evolution of PAHs in the interstellar medium (ISM) are briefly discussed.
星际多环芳烃（PAH）预计会受到真空紫外线（VUV）光子的强烈作用。在此，我们报告了通过暴露于8 - 40电子伏特范围内的同步辐射对并五苯（C₂₄H₁₂）、椭圆烯（C₃₂H₁₄）和六并苯（HBC；C₄₂H₁₈）阳离子的电离和碎片化的实验研究。结果表明，对于像并五苯这样的小分子PAH阳离子，碎片化（氢损失）比电离更重要。然而，随着尺寸增大，电离变得越来越重要，对于六并苯阳离子，电离占主导。对这些结果进行了讨论，并得出结论，对于大型PAH，只有当光子能量达到可及的最高电离势时，碎片化才变得重要。这意味着PAH比之前认为的更具光稳定性。简要讨论了该实验研究对星际介质（ISM）中PAH光化学演化的影响。
Zotero 插件