CH is one of the most spectroscopically studied diatomic molecules. The rovibronic spectra of the methylidyne radical (CH) in adiabatic and diabatic representations are obtained based on ab initio data, including 12 potential energy curves, 38 dipole moment curves, 79 spin–orbit coupling curves, and 18 electronic angular momentum coupling curves. We employed the internally contracted multireference configuration interaction method including the Davidson correction with the aug-cc-pV(5+d)Z basis set for the C atom and the aug-cc-pV5Z basis set for the H atom. The diabatic transformations are performed based on a property-based diabatisation method to remove the avoided crossings for the E ²Π–F ²Π and F ²Π–H ²Π pairs. The coupled nuclear motion Schrödinger equations are then solved using the Duo nuclear motion program to obtain the rovibronic spectra of CH for wavenumbers from 0 to 80 000 cm⁻¹ at 5000 K. An overall prediction of the rovibronic spectra of CH is provided in this work. Our results could be beneficial for future calculations of rovibronic spectra of CH and contribute to improving astronomical, chemical, and physical models.

中文翻译：

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CH 的 rovibronic 光谱的从头研究


CH 是光谱研究最多的双原子分子之一。甲基酰亚基自由基 （CH） 在绝热和非绝热表示中的罗维布罗谱基于从头计算数据获得，包括 12 条势能曲线、38 条偶极矩曲线、79 条自旋-轨道耦合曲线和 18 条电子角动量耦合曲线。我们采用了内部收缩的多参考构型交互方法，包括戴维森校正，其中 C 原子的 aug-cc-pV（5+d）Z 基集和 H 原子的 aug-cc-pV5Z 基集。非绝热变换基于基于属性的绝热化方法执行，以消除 E ²Π–F ²Π 和 F ²Π–H ²Π 对的避免交叉。然后使用 Duo 核运动程序求解耦合的核运动薛定谔方程，以获得 5000 K 时 0 至 80 000 cm⁻¹ 波数的 CH 罗维布罗光谱。这项工作提供了对 CH 的 rovibronic 光谱的总体预测。我们的结果可能有利于未来计算 CH 的 rovibric 光谱，并有助于改进天文、化学和物理模型。