High-resolution visible laser spectroscopy of HfF

The electronic spectrum of hafnium monofluoride has been investigated from 415 to 725 nm using a laser-ablation/molecular beam laser-induced fluorescence spectrometer. Several electronic systems were observed and data have been recorded at both low and high resolution. High resolution rotational analyses of the 17.4]1.5-X1.5 (0-0), 17.9]2.5-X1.5 (0-0), 19.7]0.5-X1.5 (0-0), 20.0]0.5-X1.5 (0-0), 21.1]2.5-X1.5 (0-0), 22.3]1.5-X1.5 (0-0), and 23.3]0.5-X1.5 (0-0) subbands have been carried out, resulting in accurate values for the ground and excited state effective rotational constants. Furthermore, the rotational analysis of the subbands assigned as 17.4]1.5-X1.5 (1-0) and 17.9]2.5-X1.5 (1-0) allows us to determine values of 589.7569(6) and 588.9076(6) cm⁻¹ for ΔG^′_1/2 17.4] and ΔG^′_1/2 17.9], respectively. From dispersed fluorescence data we find that ΔG^′′_1/2=670(13) cm⁻¹ for the ground state and that another low-lying electronic state lies at ∼2850 cm⁻¹. The data also suggests that a second low-lying electronic state lies at ∼5200 cm⁻¹ above the ground state.