FORMATION OF EXCITED BRCL (B3II(0+)) IN THE REACTION OF BROMINE WITH CHLORINE DIOXIDE

The reaction of Br2 with OClO is a self-propagating chain reaction which emits red and near infrared chemiluminescence (λ & >; 600 nm) owing to the B3Π(0+)-X1Σ+ transition of BrCl. The rate-controlling step {A figure is presented} is followed by reactions of BrO and ClO radicals that propagate the chain. Based on the steady state vibrational distribution determined for the B-X band system, electronically excited BrCl* (B) is believed to be formed in the reaction {A figure is presented}. The overall photon yield Φ of BrCl chemiluminescence from the Br2 + OClO reaction was found to exceed 3 × 10-3. Typical steady state BrCl* concentrations were about 3 × 107 molecule cm-3 using [OClO]0 = [Br2]0 = 2.3 × 1013 molecule cm-3. A partial rotational analysis of the B-X spectrum of BrCl has resulted in new spectroscopic constants for the ground and excited states of 81Br35Cl and of 79Br35Cl. © 1979.