Rotational analysis of the perpendicular vibrational bands of 32SF6-Ar and 32SF6-34SF6 complexes at 10.6 μm
Year: 2025
Type: article
Abstract: Sulfur hexafluoride (SF6) is widely used in the electrical and electronic industries. It is also an important green-house gas. The study of spectra and structures of weakly bound complexes containing SF6 is helpful to gain a deep understanding of the intermolecular interactions between SF6 and other atoms or molecules. The rotationally resolved spectrum of the perpendicular vibrational band of 32SF6-Ar in the 32SF6 v3 band region has been reported previously but the rotational analysis was not completed. In this work, this vibrational band of 32SF6-Ar is re-investigated. The jet-cooled rovibrational spectra of SF6/Ar/He gas mixtures are measured by a continuous-wave distributed feed-back quantum cascade laser (DFB-QCL) at 10.6 μm with a segmented- rapid-scan data acquisition scheme. The gas mixture (SF6∶Ar∶He = 0.12∶1∶100) is expanded into a cylinder vacuum chamber through a 0.8 mm pin-hole nozzle. The probe laser is reflected about 90 times by a pair of astigmatic mirrors inside the chamber. The observed spectrum is analyzed by the standard symmetric-top Hamiltonian with the program PGOPHER. When the resonance interaction between the l = \begin{document}$ \pm 1 $\end{document} levels in the double-degenerate excited vibrational state of 32SF6-Ar is considered, which was ignored in previous studies, a successful rotational analysis of the perpendicular vibrational band is conducted. The band-origin of the perpendicular band is determined to be v0 = 947.45300(58) cm–1 and the resonance interaction parameter is q = –0.002325(70) cm–1. A set of absorption lines close to the Q branch of the 32SF6 v3 band is tentatively assigned to the perpendicular vibrational band of 32SF6-34SF6 complex. This band is heavily overlapped by the monomer lines so that very few lines can be assigned. The band-origin of this band is estimated to be 948.1181(12) cm–1. These results will be useful for developing highly accurate intermolecular potential energy surfaces for SF6-Ar complex and SF6 dimer in the future.
Source: Acta Physica Sinica
Authors: Hongrui YUAN, Yun LIU, Xiang LI, Chuanxi DUAN
Institution: Central China Normal University
Language: English
Subfield: Spectroscopy
Field: Chemistry
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4412414003