Spectroscopic study of B²Σ⁺–X₁ ²Π_1/2 transition of electron electric dipole moment candidate PbF

PbF, a valuable candidate for measuring the electron electric dipole moment (eEDM), is of great significance in measuring its spectrum and deriving its molecular constants in experiment. In the present work, the rovibronic spectrum of the B^2\Sigma ^+-X_1^\, 2\Pi _1/2 transition of PbF in a wavelength range of 260 nm-285 nm is studied by the laser ablation/laser induced fluorescence method. The molecular parameters of the X_1^\, 2\Pi _1/2 (v''=0) and B^2\Sigma ^+ (v'=0, 1) states are derived from the recorded spectra of the (0, 0) and (1, 0) bands of the B^2\Sigma ^+-X_1^\, 2\Pi _1/2 transition. Also, the Franck-Condon factors (FCFs) of the transitions between the B^2\Sigma ^+ and X_1^\, 2\Pi _1/2 states are calculated by the RKR/LEVEL method and the Morse potential method, respectively.