Recent advances in circumstellar metal chemistry and laser-coolable molecules have spurred interest in the spectroscopy and electronic properties of alkaline earth metal-bearing polyatomic molecules. We report the microwave rotational spectra of two members of this important chemical family, the linear magnesium-carbon chains MgCH and MgCN, detected with cavity Fourier transform microwave spectroscopy of a laser ablation-electric discharge expansion. The rotation, fine, and hyperfine parameters have been derived from the precise laboratory rest frequencies. These experimental results, combined with a theoretical quantum chemical analysis, confirm the recent identification of MgCH and MgCN in the circumstellar envelope of the evolved carbon-rich star IRC+10216. The spectroscopic data also provide insight into the structural and electronic properties that influence the metal-based optical cycling center in this unique class of laser-coolable polyatomics.

中文翻译：

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镁碳链MgC[式略]H和MgC[式略]N的实验室旋转光谱

星周金属化学和激光可冷却分子的最新进展激发了人们对含碱土金属的多原子分子的光谱学和电子特性的兴趣。我们报告了这个重要化学家族的两个成员——线性镁碳链 MgCH 和 MgCN——的微波旋转光谱，这是用激光烧蚀-放电膨胀的腔体傅里叶变换微波光谱检测到的。旋转、精细和超精细参数源自精确的实验室静止频率。这些实验结果与理论量子化学分析相结合，证实了最近在演化的富碳恒星 IRC+10216 的星周包层中鉴定出 MgCH 和 MgCN。光谱数据还提供了对影响这种独特的激光冷却多原子类别中基于金属的光学循环中心的结构和电子特性的深入了解。