LAUSR

Abstract Several new electronic transitions of PtF have been observed in the high resolution spectra recorded in absorption using Intracavity Laser Spectroscopy (ILS). The PtF molecules were produced in a current-regulated RF discharge operating with 0.30–0.80 A applied to a Pt-lined Cu hollow cathode in 0.50–1.25 Torr of 1–5% SF6 in an Ar/He sputter gas mixture. This hollow cathode was located within the resonator cavity of a tunable DCM dye laser operating over the 14,500–16,500 cm−1 range, and effective pathlengths of 0.4–2.0 km were utilized with the ILS method. Six band systems were identified as the (2,1), (1,0), (0,0), (0,1), (1,2), and (0,2) bands of the [15.8 + x] Ω = 5/2 − B 2Δ5/2 transition. Spectral features due to 194PtF, 195PtF, 196PtF, and 198PtF were identified, and the data were fit to mass-independent Dunham-type expressions using PGOPHER. A Pt-isotope field-shift correction to the electronic excitation energy was required to model the observed transitions to within experimental uncertainty. The results of this study indicate that the [0.4] 2Δ5/2 state reported by Ng et al. must be the A 2Σ+ state of PtF, and the experimental findings correspond well with the theoretical predictions of Zou and Suo (2016).