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.