Calculations on the rates, mechanisms, and interstellar importance of the reactions between C and NH2 and between N and CH2
Calculations on the rates, mechanisms, and interstellar importance of the reactions between C and NH2 and between N and CH2
复制标题
C 和 NH2 以及 N 和 CH2 之间反应的速率、机制和星际重要性的计算
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
D. Talbi
中科院分区：
文献类型：
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作者：
E. Herbst;R. Terzieva;D. Talbi
了解星际云中HNC/HCN丰度比对温度的依赖关系的尝试已经长期存在，而且尚无定论。本文报道了对HNC和HCN的形成起重要作用的两个中性反应的量子化学和动力学研究，分别是- C+NH2HNC+H和N+CH2HCN+H。我们发现，虽然这些反应最初确实会产生天文学家提出的产物，但在这两个反应中都有如此多的多余能量，使得HCN和HNC产物能够在生产后进行有效的异构化反应。异构化导致两种异构体的生成速率接近相等，如果有足够的旋转激发，则HNC稍微有利。这一结果已被纳入我们最新的致密星际云化学模型网络中。
The attempt to understand the temperature dependence of the HNC/HCN abundance ratio in interstellar clouds has been long standing and indecisive. In this paper we report quantum chemical and dynamical studies of two neutral–neutral reactions thought to be important in the formation of HNC and HCN, respectively – C+NH2HNC+H, and N+CH2HCN+H. We find that although these reactions do lead initially to the products suggested by astronomers, there is so much excess energy available in both reactions that the HCN and HNC products are able to undergo efficient isomerization reactions after production. The isomerization leads to near equal production rates of the two isomers, with HNC slightly favoured if there is sufficient rotational excitation. This result has been incorporated into our latest chemical model network of dense interstellar clouds.