Formation of the B3Π(0+) states of BrF and IF by atom recombination in the presence of singlet (1Δg,1Σ+g) oxygen

Abstract
Combination of F 2P with Br 2P or I 2P ground state atoms in the presence of singlet O2 1Δg, 1Σ+ g, leads to formation of BrF B3Π(0+) or IF B3Π(0+), which were detected by observation of their band emission spectra (975 λ 483 nm), B3Π(0+)→X1Σ+. It was shown that formation of BrF B3Π(0+) explicitly requires energy transfer from O2 1Δg or 1Σ+ g. The most probable excitation process is envisaged to occur by combination of Br 2P+ F 2P atoms (in the presence of a third body) to give BrF A3Π(1)(or possibly 3Π(2, 0–)), followed by collisional energy transfer from singlet oxygen with BrF A3Π(1) to BrF B3Π(0+). At least 38 new bands of the B→X system of BrF have been identified, and the previously uncertain vibrational numbering of the B3Π(0+) state has been confirmed. Vibrational constants are reported for the first time for levels of the X1Σ+ ground state up to v″= 10, corresponding to an energy of 6262 cm–1 above v″= 0. The available data on the dissociation energy of BrF are briefly surveyed, and a value of D°(BrF)= 2.384 eV is favoured. For the B→X system of IF, many new bands have been observed, and vibrational constants for levels up to v″= 19 (10 381 cm–1 above v″= 0) of the ground state are reported.