Electronic excitation of bromine to the B 3?(0 + u ) state in the recombination of ground state Br2 P ? atoms

Abstract

Emission has been observed from v′⩽ 9 of the B3Π(0+u) state of Br2 formed in the recombination of two ground-state Br(2P) atoms at 298 K and near 1 Torr total pressure of argon. Measurements of relative band intensities of the Br2(B→X) system have been combined with Franck-Condon factors to show that the vibrational population distribution is thermal for 298 K in the range 5 ⩽v′⩽ 9, but that the lower levels 0 ⩽v′⩽ 4 are populated to only a small extent under these conditions. The results suggest that recombination of two Br(2P) atoms into the B3II(0+u) state occurs in the vicinity of v′= 5 via a potential energy barrier of approximately 600 cm–1.