Mid-infrared quantum cascade laser spectroscopy of the Ar-NO complex: Fine and hyperfine structure

Zhuang Liu; Wei Luo; Chuanxi Duan

doi:10.1063/1.5084755

Mid-infrared quantum cascade laser spectroscopy of the Ar-NO complex: Fine and hyperfine structure

J Chem Phys. 2019 Feb 14;150(6):064302. doi: 10.1063/1.5084755.

Authors

Zhuang Liu¹, Wei Luo¹, Chuanxi Duan¹

Affiliation

¹ College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China.

PMID: 30769989
DOI: 10.1063/1.5084755

Abstract

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 ¹⁴N (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.