IF (A→X, B→X) chemiluminescence from the F+I2F reaction

Weak IF (A→X, B→X) chemiluminescence was found to be emitted from the F+I2 reaction system under the conditions of a crossed molecular beam experiment. In addition, laser induced fluorescence product state analysis of IF formed in the electronic χ 1Σ+ state in the reaction F+I2→IF+I was carried out. This measurement resulted in a bimodal vibrational product state distribution indicating a partly direct and a partly complex mechanism. We conclude that long lived trihalogen radicals I2F are formed during the reaction F+I2. Secondary encounters of F atoms lead to the luminescent step F+I2F→IF±+IF. The exoergicity of this step is comparable with the experimentally observed B 3π(0+) state excitation. It is likely that the observed meachanism also plays a role in the iodine fluorine flame.(AIP)