The molecular frame electric dipole moment and hyperfine interactions in hafnium fluoride, HfF

The (1,0) [17.9]2.5-X(2)Δ(3∕2) band of hafnium monofluoride (HfF) has been recorded using high-resolution laser-induced fluorescence spectroscopy both field-free and in the presence of a static electric field. The field-free spectra of (177)HfF, (179)HfF, and (180)HfF were modeled to generate a set of fine and hyperfine parameter for the X(2)Δ(3∕2)(v = 0) and [17.9]2.5 (v = 1) states. The observed optical Stark shifts for the (180)HfF isotopologue were analyzed to produce the molecular frame electric dipole moments of 1.66(1) D and 0.419(7) D for the X(2)Δ(3∕2) and [17.9]2.5 state, respectively. Both the generalized effective core potential and all-electron four component approaches were used in ab initio calculations to predict the properties of ground state HfF including equilibrium distance, dipole moments, quadrupole coupling, and magnetic hyperfine constants.