Rotational Spectroscopy of 1-Cyano-2-methylenecyclopropane (C 5 H 5 N)─A Newly Synthesized Pyridine Isomer
Rotational Spectroscopy of 1-Cyano-2-methylenecyclopropane (C 5 H 5 N)─A Newly Synthesized Pyridine Isomer
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1-氰基-2-亚甲基环丙烷 (C 5 H 5 N)——一种新合成的吡啶异构体的旋转光谱
DOI：
10.1021/acs.jpca.3c08002
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发表时间：
2024
期刊：
影响因子：
--
通讯作者：
McMahon, Robert J.
中科院分区：
文献类型：
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作者：
Jean, Dairen R.;Wood, Samuel A.;Esselman, Brian J.;Woods, R. Claude;McMahon, Robert J.
首次给出了吡啶异构体1-氰基-2-亚甲基环丙烷（C1，C5H5N）的气相旋转光谱，覆盖范围为235至500 GHz。超过 3600 个基振动状态的 a、b、和 c 型转变已被分配、测量，并最小二乘拟合到具有低统计不确定性的部分八次 A 和 S 减少的扭曲转子哈密顿量 (σfit= 42 kHz)。两个最低能量基本态（ν27 和 ν26）和最低能量泛音（2ν27）的跃迁已被类似地测量、分配，并且最小二乘法适合单态哈密顿量。使用 B3LYP 和 MP2 水平的理论计算出的振动-旋转相互作用常数 (B0-Bv) 与相应的实验值进行了比较。根据我们的初步分析，接下来的几个振动激发态通过科里奥利和非谐耦合形成一个或多个相互作用态的复杂多聚体。这里提出的光谱常数和过渡频率构成了未来实验室光谱学和天文搜索 1-氰基-2-亚甲基环丙烷的基础。
The gas-phase rotational spectrum of 1-cyano-2-methylenecyclopropane (C1, C5H5N), an isomer of pyridine, is presented for the first time, covering the range from 235 to 500 GHz. Over 3600a-,b-, andc-type transitions for the ground vibrational state have been assigned, measured, and least-squares fit to partial-octic A- and S-reduced distorted-rotor Hamiltonians with low statistical uncertainty (σfit= 42 kHz). Transitions for the two lowest-energy fundamental states (ν27and ν26) and the lowest-energy overtone (2ν27) have been similarly measured, assigned, and least-squares fit to single-state Hamiltonians. Computed vibration–rotation interaction constants (B0–Bv) using the B3LYP and MP2 levels of theory are compared with the corresponding experimental values. Based upon our preliminary analysis, the next few vibrationally excited states form one or more complex polyads of interacting statesviaCoriolis and anharmonic coupling. The spectroscopic constants and transition frequencies presented here form the foundation for both future laboratory spectroscopy and astronomical searches for 1-cyano-2-methylenecyclopropane.