College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China.
J Chem Phys. 2019 Feb 14;150(6):064302. doi: 10.1063/1.5084755.
The rovibrational spectrum of the Ar-NO open-shell complex has been measured in the 5.3 µm region using distributed feed-back quantum lasers to probe the direct absorption in a slit-jet supersonic expansion. Five P-subbands, namely, P←P:1/2←3/2,1/2←1/2,3/2←1/2,5/2←3/2, and 7/2←5/2, are observed, with J up to 15.5. The hyperfine structure due to the nuclei spin of N (I = 1) can be partially resolved in the P←P:1/2←3/2,1/2←1/2, and 3/2←1/2 subbands. The fine structure of the observed spectrum is analyzed using a modified semi-rigid rotor Hamiltonian [W. M. Fawzy and J. T. Hougen, J. Mol. Spectrosc. 137, 154-165 (1989)] and an empirical Hamiltonian [Y. Kim and H. Meyer, Int. Rev. Phys. Chem. 20, 219-282 (2001)] separately. The hyperfine structure can be simulated successfully by including hyperfine terms to the semi-rigid rotor Hamiltonian. A linear J-dependence of the angle between the inertial a-axis of the complex and the intramolecular axis of the NO subunit is also introduced in order to model the strong structure relaxation effect in the P = 1/2 state.
氩-亚硝酰自由基开壳复合物的振转光谱已在 5.3μm 区域使用分布式反馈量子激光测量，以探测在狭缝射流超声速膨胀中的直接吸收。观察到五个 P 支带，即 P←P:1/2←3/2、1/2←1/2、3/2←1/2、5/2←3/2 和 7/2←5/2，其中 J 高达 15.5。由于 N 的核自旋（I = 1）引起的超精细结构可以在 P←P:1/2←3/2、1/2←1/2 和 3/2←1/2 支带中部分分辨。使用改进的半刚性转子哈密顿量[W. M. Fawzy 和 J. T. Hougen，J. Mol. Spectrosc. 137，154-165（1989）]和经验性哈密顿量[Y. Kim 和 H. Meyer，Int. Rev. Phys. Chem. 20，219-282（2001）]分别分析观察到的光谱的精细结构。通过将超精细项包含在半刚性转子哈密顿量中，可以成功模拟超精细结构。为了模拟 P = 1/2 态中强结构弛豫效应，还引入了复合物惯性 a 轴与 NO 亚基内分子轴之间角度的线性 J 依赖性。
