The A(0+)−X(0+) transition of BiBr: radiative lifetimes of the A state Original Research Article

Laser induced fluorescence from resolved rovibrational levels (ν′, J′) of the electronically excited A(0+) state of BiBr has been observed. Fluorescence lifetimes for several rovibrational levels (ν′, J′) of the BiBr A(0+) state in the ν′ = 4–9 interval have been measured, and a study of their variation with pressure has been made. No significant variations of radiative lifetimes from specific vibrational levels ν′ (ν′ = 0–9) of the BiBr A excited state has been observed, and no dependence on the rotational energy, within a vibrational level, was detected for the measured lifetimes. A collision-free radiative lifetime of τ0 ≈ 0.52 μs is proposed for the BiBr A(0+) state and values for quenching rate constants in the order of kQ ≈ (1.0 ± 0.3) × 10−11 cm3 molecule−1 s−1 in the spectral range studied were obtained. From calculated Franck-Condon factors for the ν′−ν′ʹ transitions of the A-X system and from our radiative lifetimes, electronic transition moments have been calculated.