HC2H+ (n = 2-6) 链的气相电子光谱
Samuel J P Marlton1, Chang Liu1, Patrick Watkins1
1School of Chemistry, University of Melbourne, Parkville 3010, Australia. evanjb@unimelb.edu.au.
Physical chemistry chemical physics : PCCP
|April 16, 2024
概括
研究人员使用光谱学研究奇数碳链 (HC2n+1H+). 虽然HC11H+与分散的星际波段相匹配,但其他链没有,质疑其载体作用.
科学领域:
- 天体化学和分子光谱学
- 星际介质的组成 星际介质的组成
背景情况:
- 高度不和的碳链在燃烧,电放电和星际介质中普遍存在.
- 用原子 (聚乙烯) 封顶的线性碳链在富含的环境中很常见.
- 虽然偶数碳链 (HC2nH2+) 的特征很好,但奇数碳链 (HC2n+1H+) 的理解较少.
研究的目的:
- 用光谱检测奇数碳链 (HC2n+1H+,n=2-6) 的电子特性.
- 确定这些链是否可能导致观测到的分散星际带 (DIB).
主要方法:
- 采用了双色共振增强光解离谱学.
- 链条是通过自上而下 (pyrene碎片) 或自下而上 (碳集群和乙烯反应) 的方法生成的.
- 种类被限制和冷却在一个冷四极离子陷.
- 离子移动性测量证实了线性结构.
主要成果:
- 在可见/近红外范围内测量了HC2n+1H+ (n=2-6) 的电子光谱.
- 斯佩克特显示了三带系统,每增加C2H子单位的红色偏移逐渐达到90nm.
- 最强的HC11H+波段 (λ=545.1 nm) 与5450 Å. 的强分散星际波段 (DIB) 非常接近.
- 其他HC11H+带和短链带与已知的DIBs没有相关.
结论:
- 值得注意的是,HC11H+与5450 Å DIB的密切匹配,但其他频段的差异使人们怀疑HC11H+是唯一的载体.
- 由于其他HC2n+1H+链缺乏相关性,因此可以对它们的星际柱密度设置上限.
- 需要进一步的研究才能完全分配DIB载体,并了解这些碳链在太空中的作用.
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