Abstract:

This study presents the preparation of PbF radicals via the reaction of Pb plasma, generated by the laser ablation of lead, with SF₆/Ar gas mixture. Moreover, the vibrational-rotational bands of the ${\rm{A}}^2{\text{∑}}^{ +}$–X²Π_1/2 transition of PbF molecule were measured using laser induced fluorescence spectroscopy. The molecular constants $ {T}_{0} $, $ B $, $ D $, $ \gamma $ and $ p $ for the vibrational levels $ v $ = 0 and $ v $ = 1 of the PbF molecule in the ${\rm{A}}^2{\text{∑}}^{ +}$ state. The data provide effective information for electronic electric dipole moment(eEDM) measurement. Additionally, the fluorescence lifetime of the PbF molecule in the $v=0$ vibrational state of the ${\rm{A}}^2{\text{∑}}^{ +}$ state was measured. Finally, the Franck-Condon factors for the ${\rm{A}}^2{\text{∑}}^{ +}$–X²Π_1/2 transition were calculated using the Morse potential and Rydberg-Klein-Rees inversion(RKR)/LEVEL methods, indicating that PbF molecules are unsuitable for laser cooling research. The above results enrich the understanding of PbF molecular spectrum and provide key references for future studies on precise eEDM measurements.

Key words: electronic electric dipole moment(eEDM), PbF molecule, laser induced fluorescence spectroscopy technology, spectral constants, Frank-Condon factors