Laser-induced fluorescence studies: B–X transition of Cl2. Part 2.—Transition from bound to unbound excited states
Abstract
Laser-induced fluorescence has been used to determine the collision-free lifetimes of resolved ro-vibrational levels (v′, J′) of the excited B3Π(0+u) states of 35Cl35Cl and 35Cl37Cl. Predissociation affects all vibrational states above v′= 12, giving undetectably weak fluorescence and lifetimes estimated to be 3 ns.
Lifetimes of selected rotational levels of the stable (v′, J′) states were determined for 12 v′
7. The mean collision-free lifetime for these states was τ0=(83 ± 5)µs.
Observations on the highest-energy (12, J′) states before predissociation have provided close upper limits for the dissociation energy D00(35Cl35Cl) and D00(35Cl37Cl). There is a negligible energy barrier to predissociation of B-states. Predissociation of the B-state of Cl2 occurs by crossing with the 1Π(1u) repulsive state at a relatively short internuclear distance.