Vibrational nonequilibrium dissociation of Br2 in collisions with Ar and Br atoms

The collision induced dissociation processes in dilute mixtures of Br2–Ar and Br2–Br are investigated. Vibrational transition rates and dissociation rates from individual vibrational levels are derived from quasiclassical Monte Carlo trajectory calculations where only vibrational nonequilibrium effects are considered. The full transition rate matrix is completed by a moment analysis of the trajectory results. From the steady state solution of vibrational-level master equations, it is found that steady state populations in excited vibrational states are largely depleted but the nonequilibrium dissociation rates are about 30%–75% less than the equilibrium rates. The low activation energy observed in the previous experiments in the dissociation process, Br2+Br→Br+Br+Br cannot be explained by the present analysis.