Photodissociation Exploration for Near-Visible UV Absorption of Molecular Bromine

The photodissociation of Br2 was investigated within the near-visible UV absorption band. Based on thepotential curves for the ground and low-lying excited states, the optical cross-sections for the discrete transitions of C1Πu, B3Π+0u, A3Π1u <—X1Σ+g and their total energy absorption spectrum are derived, and the quantum yield of (Br+Br*) channel are determined correspondingly. The one-dimensional Landau-Zener model is used to evaluate the behavior of curve crossing during photodissociation. The results indicate that the influence of nonadiabatic mechanism, which may be caused by the electronic-vibrational interplay between the B and C states, is negligibly small for the (Br+Br*) channel. From the Landau-Zener modeling of the observed product recoil parameter fi(Br+Br), the best-fit value of the coupling matrix element or coupling strength between the diabatic B and C state potentials is obtained.