Theoretical treatment of the spontaneous predissociation of Br2, B 3Π(0u+)

The spontaneous heterogeneous predissociation of the B 3Π(0u+) state of bromine is discussed. Theoretical treatment of the heterogeneous interaction is presented, with emphasis placed on the role of the Franck–Condon principle in predissociation. Numerically generated vibrational wave functions are used to calculate predissociation probabilities for the B state. From these calculations the parameters of the repulsive potential responsible for the predissociation are determined, and this potential curve is identified as the 1Π(1u) state. Good agreement with experimental results was obtained with a 1Πu potential of the form U(R) = 1.594×104/R9.384. This crosses the B state curve between v′ = 4 and 5, which is two levels higher than indicated in previous work. The new 1Πu curve is compatible with other theoretical and experimental results.