Broadening and shifting coefficients of rovibrational lines of HF perturbed by He in the fundamental and first overtone regions

The spectra of gaseous hydrogen fluoride in the mixture with He were recorded in the regions of the fundamental bands and the first overtone of HF using the stainless cell equipped with sapphire windows at a resolution of 0.005 cm⁻¹. Each individual rovibrational line in these bands was fitted using a Voigt profile. The pressure dependences of Voigt profile parameters (frequency of maximum and Lorentzian width) were determined at constant partial pressure of HF. From these dependences, shifting and broadening coefficients were derived through linear regression analysis. These coefficients were independently derived through an alternative methodology. These coefficients were treated as fitting parameters, when the complete set of spectra at constant HF partial pressure was fitted simultaneously. Both methods gave the close results. The special program was developed to realize the second method. It opens the possibility to use advanced profiles to fit the experimental lines.

The coefficients were obtained for the lines with lines numbers m = −10...+10 both in the fundamental and overtone regions. Most of the values, especially for the overtone transitions, are novel. The obtained data were compared with existing literature data of HF-He system as well as with HCl-He, HBr-He, and HI-He systems [1,2].

1. G. Li, R.E. Asfin, A.V. Domanskaya, V. Ebert, Molecular Physics116 3495–3502 (2018).
2. A.V. Domanskaya, M.O. Bulanin, K. Kerl, C. Maul, J. Mol. Spectrosc. 253 20–24 (2009).

The study was supported by Resource Centers "Geomodel" and "Cryogenic department" of of the Science Park of the Saint Petersburg State University