Laboratory investigation of the gas-phase formation of (poly)cyclic hydrocarbons under interstellar conditions

星际条件下（多）环烃气相形成的实验室研究

• 批准号: 2308045
• 负责人: Jordy Bouwman
• 金额: $ 41.87万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2308045&HistoricalAwards=false
• 关键词: Laboratory; investigation; gas; phase; formation

Cyclic molecules composed of five or six carbon atoms, as well as small polycyclic aromatic hydrocarbons (PAHs) represent the most complex molecules unambiguously identified by radio astronomy in cold dark molecular clouds, but little is known about how they are formed under interstellar conditions. Using a combined experimental and computational approach, this research project will investigate key gas phase reaction mechanisms driving the formation of complex cyclic hydrocarbons in cold interstellar clouds. Results from the project will serve as critical input to astrochemical models, allowing astronomers to explain the presence of complex cyclic hydrocarbons in space. This project will train a graduate student in methods of advanced laboratory astrophysics and provide research opportunities to an undergraduate student. The research team will investigate the reactivity of two radical species, ortho-benzyne and 2,3-pyridyne. The investigators have shown that ortho-benzyne, a molecule recently identified in the Taurus Molecular Cloud (TMC-1), plays a crucial role in the synthesis of the complex hydrocarbons ethynylcyclopentadiene and indene which have also been identified there. This project will build upon that work by investigating reactions of ortho-benzyne and 2,3-pyridyne that potentially form the PAH naphthalene, as well as the cyanocyclopentadienes which have been detected in TMC-1. A pyrolysis microreactor coupled to a double imaging photoelectron photoion coincidence (i2PEPICO) spectrometer connected to the vacuum ultraviolet beamline of a synchrotron will be used in the study. The i2PEPICO system will be capable of measuring---with isomer specificity---the products formed in chemical reactions of the selected radical species. Quantum chemical calculations of potential energy surfaces will yield insights into the reactions and a statistical model will be employed to derive product branching fractions. Because the reactions investigated have the potential to yield products that are plausible candidates for detection in space, results from this study would also guide future radio astronomical observations. Besides astronomy, results from this project are directly applicable to PAH and soot formation mechanisms in combustion chemistry.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

由五个或六个碳原子组成的环状分子以及小的多环原子（PAHS）代表了射电天文学在冷暗分子云中明确鉴定出的最复杂的分子，但对它们在星际条件下如何形成的鲜明的人数鲜为人知。 该研究项目使用合并的实验和计算方法，将研究驱动冷星际云中复杂环状烃的形成的关键气相反应机制。 该项目的结果将是对天体化学模型的关键输入，从而使天文学家可以解释空间中复杂的环状烃的存在。 该项目将培训一名研究生高级实验室天体物理学方法，并为本科生提供研究机会。研究小组将研究两种激进物种Ortho-Benzyne和2,3-吡啶的反应性。研究人员表明，最近在金牛座分子云（TMC-1）中鉴定出的分子Ortho-Benzyne在合成复杂的碳氢化合物乙烯甲甲基二烯和Indene的合成中起着至关重要的作用。 该项目将通过调查可能形成PAH萘的Ortho-Benzyne和2,3-吡啶的反应以及在TMC-1中检测到的Cyanocyclopentadienes的反应。 研究将在研究中使用的热解微反应器与双成像光电子光照射复合（I2PEPICO）光谱仪连接到同步基因的真空紫外线线相连。 I2Pepico系统将能够用异构体特异性进行测量---在选定的自由基物种的化学反应中形成的产物。 势能表面的量子化学计算将产生对反应的见解，并将采用统计模型来得出产品分支分支。 由于所研究的反应有可能产生合理的空间检测的产品，因此这项研究的结果还将指导未来的射电天文观测。 除天文学外，该项目的结果直接适用于PAH和燃烧化学中的烟灰组机制。该奖项反映了NSF的法定任务，并且使用基金会的知识分子优点和更广泛的影响审查标准，认为值得通过评估来支持。