论文标题
冰结构对嵌入在固体水中的PAH的软紫外光化学的影响
Influence of the ice structure on the soft UV photochemistry of PAHs embedded in solid water
论文作者
论文摘要
长期以来，已知多孔无定形固体水中多环芳烃（PAHS）的紫外线光反应性既形成了氧化的光产物和光碎屑。这项研究的目的是检查冰结构对软紫外线辐射条件下反应性的影响。 PAH与无定形固体水（多孔和紧凑）以及晶体（立方和六边形）冰的混合物在高的真空室中制备，并使用汞灯辐照长达2.5小时。结果表明，含氧PAH的产生仅在无定形水冰中有效，而在无定形和结晶冰中都可能发生碎裂。我们得出的结论是，反应性是由PAH - 水相互作用在有利的几何形状中驱动的，尤其是在孔隙表面可用的悬挂键。这些结果表明，含氧PAH分子的形成最有可能发生在具有多孔（或紧凑的）无定形固体水的星际环境中，并且这种反应性可能会极大地影响陨石中芳香剂的库存。
The UV photoreactivity of polycyclic aromatic hydrocarbons (PAHs) in porous amorphous solid water has long been known to form both oxygenated photoproducts and photofragments. The aim of this study was to examine the influence of the ice structure upon reactivity under soft UV irradiation conditions. Mixtures of PAHs with amorphous solid water (porous and compact) and crystalline (cubic and hexagonal) ices were prepared in a high vacuum chamber and irradiated using a mercury lamp for up to 2.5 hours. The results show that the production of oxygenated PAHs is efficient only in amorphous water ice, while fragmentation can occur in both amorphous and crystalline ices. We conclude that the reactivity is driven by PAH-water interactions in favourable geometries, notably where dangling bonds are available at the surface of pores. These results suggest that the formation of oxygenated PAH molecules is most likely to occur in interstellar environments with porous (or compact) amorphous solid water and that this reactivity could considerably influence the inventory of aromatics in meteorites.
