Excited state photochemically driven surface formation of benzene from acetylene ices on Pluto and in the outer solar system
Excited state photochemically driven surface formation of benzene from acetylene ices on Pluto and in the outer solar system
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冥王星和太阳系外乙炔冰的激发态光化学驱动表面形成苯
DOI：
10.1039/d1cp04959c
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发表时间：
2022
影响因子：
3.3
通讯作者：
Ralf I. Kaiser
中科院分区：
文献类型：
--
作者：
N. Fabian Kleimeier;Yiwei Liu;Andrew M. Turner;Leslie A. Young;Chih-Hao Chin;Tao Yang;Xiao He;Jen-Iu Lo;Bing-Ming Cheng;Ralf I. Kaiser
美国宇航局的新视野号任务揭示了冥王星表面的多样化景观，其中大片区域呈中性颜色，而克苏鲁黄斑等其他区域的颜色从金黄色到红色不等，占冥王星碳预算的一半。在这里，我们在实验室实验中结合电子结构计算证明，低能紫外光子对固体乙炔（冥王星表面最丰富的沉淀物）的光解可通过激发态光化学有效合成苯和多环芳烃，从而为有色表面材料提供关键的分子构建块。由于低能光子向冥王星表面传递的剂量比宇宙射线的剂量高出六个数量级，因此这些过程可能会对冥王星表面和太阳系天体（例如海卫一）碳氢化合物覆盖的表面的着色产生重大影响。这一发现极大地增强了我们对整个太阳系中芳香分子和碳分布的感知。
NASA's New Horizons mission unveiled a diverse landscape of Pluto's surface with massive regions being neutral in color, while others like Cthulhu Macula range from golden-yellow to reddish comprising up to half of Pluto's carbon budget. Here, we demonstrate in laboratory experiments merged with electronic structure calculations that the photolysis of solid acetylene – the most abundant precipitate on Pluto's surface – by low energy ultraviolet photons efficiently synthesizes benzene and polycyclic aromatic hydrocarbons via excited state photochemistry thus providing critical molecular building blocks for the colored surface material. Since low energy photons deliver doses to Pluto's surface exceeding those from cosmic rays by six orders of magnitude, these processes may significantly contribute to the coloration of Pluto's surface and of hydrocarbon-covered surfaces of Solar System bodies such as Triton in general. This discovery critically enhances our perception of the distribution of aromatic molecules and carbon throughout our Solar System.