New highly exothermic formation pathways incorporating both thermodynamic and kinetic control for the newly astronomically detected H₂CNCN molecule are paired with extremely accurate quantum chemical rovibrational spectroscopic computations. The reactions between astronomically known CH₂CN/CH₂CCH + HNCN follow effectively identical pathways and proceed through stable intermediates and over deeply submerged transition states to form H₂CNCN and HCN/HCCH coproducts. Similarly, the reaction between CH₂CN and NCN⁻ can also form H₂CNCN, although this pathway first requires the initial formation of NCN⁻, which is currently undetected in space, via HNCN + CN⁻. This two-step mechanism uses the highly abundant CN⁻ as the catalyst. Incredibly accurate quantum chemical spectroscopic data are reported for all reactants and products of these reactions, with errors between experimental values and the computations herein on the order of 0.1% or less. Anharmonic vibrational frequencies and intensities are also reported in order to guide experimental and observational searches for these molecules that have mostly been detected in the radio but may now be detectable via JWST.

中文翻译：

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关于 H2CNCN 及其祖先的形成和可检测性


新的高放热形成途径结合了新天文学检测到的 H ₂ CNCN 分子的热力学和动力学控制，并与极其精确的量子化学旋转光谱计算相结合。天文学上已知的 CH ₂ CN/CH ₂ CCH + HNCN 之间的反应实际上遵循相同的途径，并通过稳定的中间体和深度淹没的过渡态进行，形成 H ₂ CNCN 和 HCN/HCCH 副产物。类似地，CH ₂ CN 和NCN ^-之间的反应也可以形成H ₂ CNCN，尽管该途径首先需要通过HNCN + CN ^-初步形成NCN ^- ，目前在太空中尚未检测到NCN - 。这种两步机制使用高度丰富的 CN ^-作为催化剂。这些反应的所有反应物和产物都报告了极其精确的量子化学光谱数据，实验值和本文计算值之间的误差约为 0.1% 或更小。还报告了非谐波振动频率和强度，以指导对这些分子的实验和观察搜索，这些分子主要在无线电中检测到，但现在可以通过 JWST 检测到。