Analysis of the 0-0, 1-0, and 2-0 Bands of the [18.09]4 (5Δ4) -X4 (5Δ4) and [18.46]3 (5Δ3) – X3 (5Δ3) transitions of ruthenium monoxide (RuO)

Laser Induced Fluorescence (LIF) has been used to study the spectroscopy of ruthenium monoxide (RuO) in the UNB laser-ablation molecular-jet apparatus. High-resolution spectra of the 0–0, 1–0 and 2–0 bands of the [18.09]4 – X4 and [18.46]3 – X3 transitions have been obtained with a linewidth (FWHM) of ∼100 MHz. Rotational structure of six individual isotopologues 96RuO, 99RuO, 100RuO, 101RuO, 102RuO and 104RuO was well resolved and used to examine the rotational and vibrational isotope effects. In addition, hyperfine structure due to the nuclear spin (I = 5/2) of 99Ru and 101Ru has been resolved and used as an aid in establishing the electron configurations of the electronic states. The relative hyperfine widths in the Ω = 4 and 3 states are shown to be consistent with their assignment as components of 5Δ states. [Display omitted] •High-resolution spectra of RuO at 100 MHz linewidth•Analysis of resolved spectra of 6 individual (Ru) isotopologues of RuO•Resolved and analysed hyperfine structure of 99RuO and 101RuO isotopologues•Interpreted hyperfine structure as indicator of dominant electron configuration