Gas-phase formation of silicon monoxide via non-adiabatic reaction dynamics and its role as a building block of interstellar silicates
Gas-phase formation of silicon monoxide via non-adiabatic reaction dynamics and its role as a building block of interstellar silicates
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通过非绝热反应动力学气相形成一氧化硅及其作为星际硅酸盐构建块的作用
DOI：
10.1039/d2cp02188a
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发表时间：
2022
影响因子：
3.3
通讯作者：
Kaiser, Ralf I.
中科院分区：
文献类型：
--
作者：
He, Chao;Luo, Yuheng;Doddipatla, Srinivas;Yang, Zhenghai;Millar, Tom J.;Sun, Rui;Kaiser, Ralf I.
一氧化硅（SiO）被归类为星际硅酸盐纳米颗粒的关键前体和基本分子构建块，其在与生命起源相关的分子构建块的合成中发挥重要作用。在寒冷的星际介质中，一氧化硅在引发一系列基本化学反应中至关重要，这些反应导致更大的硅氧化物并最终形成硅酸盐。迄今为止，导致气相一氧化硅的基本形成机制和化学动力学在很大程度上仍然难以捉摸。在这里，通过交叉分子束实验和电子结构计算之间的协同努力，它揭示了，而不是形成高度稳定的二氧化硅（SiO2），一氧化硅可以形成通过一个势垒，放能，单碰撞事件之间的基态分子氧和原子硅涉及非绝热反应动力学通过各种系统间的交叉。我们的研究提供了有说服力的证据，在冷分子云中高度旋转振动激发的一氧化硅的可能来源，从而启动了复杂的放能反应链，最终导致在我们的银河系低温下的硅酸盐人口。
Silicon monoxide (SiO) is classified as a key precursor and fundamental molecular building block to interstellar silicate nanoparticles, which play an essential role in the synthesis of molecular building blocks connected to the Origins of Life. In the cold interstellar medium, silicon monoxide is of critical importance in initiating a series of elementary chemical reactions leading to larger silicon oxides and eventually to silicates. To date, the fundamental formation mechanisms and chemical dynamics leading to gas phase silicon monoxide have remained largely elusive. Here, through a concerted effort between crossed molecular beam experiments and electronic structure calculations, it is revealed that instead of forming highly-stable silicon dioxide (SiO2), silicon monoxide can be formed via a barrierless, exoergic, single-collision event between ground state molecular oxygen and atomic silicon involving non-adiabatic reaction dynamics through various intersystem crossings. Our research affords persuasive evidence for a likely source of highly rovibrationally excited silicon monoxide in cold molecular clouds thus initiating the complex chain of exoergic reactions leading ultimately to a population of silicates at low temperatures in our Galaxy.