一项关于星际C3H异构体形成的综合实验和理论研究
R I Kaiser1, C Ochsenfeld, M Head-Gordon
1Department of Chemistry, University of California, Berkeley, CA 94720, USA.
概括
这项研究表明,碳原子和乙之间的反应形成C3H激素,这对星际化学至关重要. 这种原子中性途径解释了在诸如TMC-1这样的宇宙云中观察到的丰度比率.
科学领域:
- 天体化学是天体化学.
- 化学动力学 化学动力学
- 量子化学 是一个量子化学.
背景情况:
- 星际环境中含有复杂的有机分子.
- 碳基分子的形成途径尚未完全理解.
- 离子-分子反应是C3H基的主要假设合成路径.
研究的目的:
- 研究基态碳原子和乙之间的反应动态.
- 确定循环和线性C3H异构体 (c-C3H和l-C3H) 的形成机制.
- 评估原子中性反应在星际C3H合成中的作用.
主要方法:
- 单次碰撞条件使用交叉光束实验.
- 最先进的 ab initio 量子化学计算.
- 碳交换反应通道的实验性识别.
主要成果:
- 碳原子和乙之间的反应产生c-C3H和l-C3H同体.
- 对两种异构体都确定了碳交换机制.
- 这种原子中性反应是C3H形成的重要途径.
结论:
- 原子中性反应为星际C3H合成提供了离子分子通路的替代方案.
- 这些发现解释了与IRC+10216.6相比,在TMC-1中观察到的c-C3H与l-C3H的比率更高.
- 这种反应对于理解暗云中的分子复杂性至关重要.
相关概念视频
Constitutional Isomers of Alkanes
Organic compounds of the same molecular formula can have different structural formulas called constitutional isomers, and the phenomenon is known as constitutional isomerism. Alkanes with four or more carbons showing multiple structures with the same molecular formula thereby exhibit constitutional isomerism.
The linear isomer of an alkane is prefixed by the term “n”; hence a linear isomer of pentane is known as n-pentane. Based on the type of branching, some of the branched isomers are given...
The linear isomer of an alkane is prefixed by the term “n”; hence a linear isomer of pentane is known as n-pentane. Based on the type of branching, some of the branched isomers are given...
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In an organic molecule, free rotation about the carbon-carbon single bond results in energetically different conformers of the molecule. Due to this rotation, called the internal rotation, ethane has two major conformations — staggered and eclipsed.
Staggered conformation is a low energy and more stable conformation with the C-H bonds on the front carbon placed at 60°dihedral angles relative to the C-H bonds on the back carbon, leading to a reduced torsional strain. In staggered ethane, the...
Staggered conformation is a low energy and more stable conformation with the C-H bonds on the front carbon placed at 60°dihedral angles relative to the C-H bonds on the back carbon, leading to a reduced torsional strain. In staggered ethane, the...
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This lesson discusses the stability of substituted cyclohexanes with a focus on energies of various conformers and the effect of 1,3-diaxial interactions.
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
Disubstituted Cyclohexanes: cis-trans Isomerism
Depending upon the different spatial orientation of the substituents, the disubstituted cycloalkanes exhibit two types of stereoisomers. The cis isomers have the substituents on the same side of the ring, whereas the trans isomers have the substituents on the opposite sides. These stereoisomers exhibit different physical properties and cannot be interconverted without breaking the carbon-carbon bonds.
In cyclohexane, the substituents can occupy different positions generating distinct isomers.
In cyclohexane, the substituents can occupy different positions generating distinct isomers.
Isomerism
Isomers are molecules with the same molecular formula but different structural arrangements. Isomers can be further classified into constitutional isomers and stereoisomers. Constitutional isomers differ in the connectivity of their constituent atoms. For example, 2-butanol and diethyl ether are constitutional isomers, as they have the same chemical formula, C4H10O, but differ in the connectivity of the carbon and oxygen atoms. Constitutional isomers have different physical and chemical...
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In this lesson, we delve into the role of ring conformation and its stability, which determines the spatial arrangement and, consequently, the molecular symmetry and stereoisomerism of cyclic compounds. 1,2-Dimethylcyclohexane is used as a case study to evaluate the possible number of stereoisomers. Here, given the multiple (n = 2) chiral centers, there are 2n = 4 possible configurations that lack a plane of symmetry, as the ring skeleton exists in a non-planar chair conformation. In addition,...


