ELECTRONIC STATES AND SPECTRA OF BIO

Abstract The electronic spectrum of the BiO radical has been studied by Fourier transform emission spectroscopy, laser-induced fluorescence, and excimer laser photolysis techniques. Six new electronic states, A 1 (Ω = 3/2) ( T e = 11 528.8 cm −1 , ω e = 530.4 cm −1 , ω e x e = 2.42 cm −1 ), G (Ω = 3/2) ( T e = 20 273 cm −1 , ω e = 499 cm −1 , ω e x e = 2.6 cm −1 ), H (Ω = 1/2) ( T e = 20 469.76(6) cm −1 , ω e = 471.63(18) cm −1 , ω e x e = 2.153(35) cm −1 ), I (Ω = 1/2) ( T e = 21 982.50(2) cm −1 , ω e = 506.50(11) cm −1 , ω e x e = 3.263(34) cm −1 ), J (Ω = 3/2) ( T e = 25 598.95(42) cm −1 , ω e = 489.95(16) cm −1 , ω e x e = 2.309(45) cm −1 ), and K (Ω = 1/2) ( T e = 26 744.7(2) cm −1 , ω e = 420.6(4) cm −1 , ω e x e = 5.25(5) cm −1 ), and 14 new electronic transitions ( A 1 ← X 1 , G → X 2 , H ↔ X 1 , H → A 2 ( A ), I ↔ X 1 , I → A 2 , J ↔ X 1 , J ↔ X 2 , K ↔ X 1 , K ↔ X 2 , K → A 2 , B ↔ X 2 , B → A 2 , C ↔ X 2 ) have been detected. Time-resolved measurements of the fluorescence decays have yielded the radiative lifetimes of the v = 0 levels of most states up to −1 energy (τ X2 = 480 ± 100 μs, τ A2 = 9.3 ± 1.5 μs, τ H = 15 ± 3 μs, τ I = 16 ± 3 μs, τ J = 4.9 ± 0.9 μs, τ K = 2.6 ± 0.3 μs, τ B = 0.55 ± 0.08 μs, τ C = 0.84 ± 0.15 μs) and rate constants for quenching of the states by some rare gas atoms and simple molecules. The new electronic states A 1 , G , H , I , J , and K and the previously known levels X 1 , X 2 , A 2 ( A ), B , C , and D are assigned to spin–orbit states arising from low-energy valence configurations of BiO with the help of detailed theoretical data calculated by Alekseyev et al. ( J. Chem. Phys. 100, 8956–8968 (1994)).