乙离子 (C2H5+) 与乙烯 (C2H2) 的反应性:一个综合实验和理论研究
Vincent Richardson1,2, Miroslav Polášek3, Claire Romanzin4,5
1Department of Physics, University of Trento, 38123 Trento, Italy.
Molecules (Basel, Switzerland)
|February 24, 2024
概括
乙基和乙烯之间的反应主要形成C3H3+和甲,小路产生C4H5+和. 这些发现对于理解星际和行星大气化学是至关重要的.
科学领域:
- 物理化学 物理化学
- 天体化学是天体化学.
- 血科学是一门科学课.
背景情况:
- 乙基 (C2H5+) 是碳化合物化学中的一个关键中间体.
- 了解它与乙烯等不和碳化合物的反应对于天体化学模型至关重要.
研究的目的:
- 重新研究乙基和乙烯之间的气相反应.
- 测量绝对反应性横截面和跨热和超热能的分支比.
- 用理论计算和实验数据阐明反应机制.
主要方法:
- 在单次碰撞条件下进行并列引导的离子束质谱.
- C2H5Br的离散光离子化产生乙基离子.
- 在理论的G4层面上进行理论计算.
- 质量分析离子运动能 (MIKE) 谱学.
主要成果:
- 在~0.1 eV确定了两个主要产品通道:C3H3+ + CH4 (BR=0.76±0.05) 和C4H5+ + H2 (BR=0.22±0.02).
- 第三个通道 (C2H3+ + C2H4) 在高的内部激发和碰撞能量出现.
- 取决于能量的速率常数范围从4.3×10-11到5.2×10-10 cm3·分子-1·s-1.
- 理论计算显示了两个主要产品道的共同中间路径.
结论:
- 反应过程通过一种共同的共价键中间体,CH3CH2CHCH+.
- 循环和线性C3H3+异构体都是通过无障碍的外热通道形成的.
- 较小的C4H5+产物形成涉及多个异构化步骤.
- 结果为星际介质化学和行星大气的模型提供了信息.
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