Laser-induced fluorescence spectroscopy of uranium monofluoride

The laser-induced fluorescence excitation spectra of uranium monofluoride have been recorded in the range of 17000-19000 cm⁻¹ using two-dimensional spectroscopy. High resolution dispersed fluorescence spectra and time-resolved fluorescence spectroscopy were also recorded. Three rotationally resolved bands were intensively analyzed, and all bands were found to be derived from the ground state X(1)4.5 with a rotational constant of 0.23421 cm⁻¹. The low-lying electronic states were observed near 435 and 651 cm⁻¹ in the dispersed fluorescence spectra, which were assigned as Ω′ = 3.5 and 2.5, respectively. The vibrational constants for the X(1)4.5 and X(1)3.5 states were calculated. The branching ratios of the dispersed fluorescence spectra for the [18.62]3.5, [17.72]4.5, and [17.65]4.5 states were reported. Radiative lifetime of 332(9) ns, 825(49) ns, and 433(15) ns for the [18.62]3.5, [17.72]4.5, and [17.65]4.5 states were obtained by fitting the time-resolved fluorescence spectroscopy, respectively. Transition dipole moments were performed using the branching ratios and the radiative lifetimes.