Kinetics and spectroscopy of electronically excited BiO obtained by energy transfer from metastable O2. I. Dependence of excitation on [O2]

Electronic States and Spectra of BiO

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, A1 (Omega = 3/2) (Te = 11 528.8 cm-1, omegae = 530.4 cm-1, omegaexe = 2.42 cm-1), G (Omega = 3/2) (Te = 20 273 cm-1, omegae = 499 cm-1, omegaexe = 2.6 cm-1), H (Omega = 1/2) (Te = 20 469.76(6) cm-1, omegae = 471.63(18) cm-1, omegaexe = 2.153(35) cm-1), I (Omega = 1/2) (Te = 21 982.50(2) cm-1, omegae = 506.50(11) cm-1, omegaexe = 3.263(34) cm-1), J (Omega = 3/2) (Te = 25 598.95(42) cm-1, omegae = 489.95(16) cm-1, omegaexe = 2.309(45) cm-1), and K (Omega = 1/2) (Te = 26 744.7(2) cm-1, omegae = 420.6(4) cm-1, omegaexe = 5.25(5) cm-1), and 14 new electronic transitions (A1 <-- X1, G --> X2, H left and right arrow X1, H --> A2(A), I left and right arrow X1, I --> A2, J left and right arrow X1, J left and right arrow X2, K left and right arrow X1, K left and right arrow X2, K --> A2, B left and right arrow X2, B --> A2, C left and right arrow X2) 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 <30 500 cm-1 energy (tauX2 = 480 +/- 100 µs, tauA2 = 9.3 +/- 1.5 µs, tauH = 15 +/- 3 µs, tauI = 16 +/- 3 µs, tauJ = 4.9 +/- 0.9 µs, tauK = 2.6 +/- 0.3 µs, tauB = 0.55 +/- 0.08 µs, tauC = 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 A1, G, H, I, J, and K and the previously known levels X1, X2, A2(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)). Copyright 1998 Academic Press.