The emission spectrum Of Br2 in the ultraviolet ( 180≤λ≤nm) has been examined in electron beam pumped rare gas-hydrogen bromide (HBr) gas mixtures. Temporally resolved and rare gas pressure-dependent studies of the Br2 fluorescence at 292 (D′→A′), 312,334, and 358 nm indicate that the formation processes for Br2 ion pair states differ for Ne and Ar diluents. Experimental evidence suggests that Br2 excited states in the first tier [correlated with Br- (1S0) + Br + (3P2) ] in Ar/HBr mixtures are formed by ion-ion recombination in which Br+ (3P2) is produced by charge transfer between Ar+ (2P) and HBr, followed by predissociation of HBr+ (A 2Σ +). In Ne buffer, Br2 states well above D′ are apparently produced by Penning ionization of HBr by Ne 3s 3P followed by recombination of Br+ (3P0,1,2) ions with Br- (1S0). Also, Ar is effective in collisionally relaxing the lowest manifold of six Br2 ion pair states but both Ne and Ar are poor quenchers of the D′ (2g) level.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry