Laboratory Studies of OBrO

UV/vis absorption cross sections for gas phase OBrO at room temperature were measured using a fast gas flow absorption cell and a diode array spectrometer. The OBrO concentration was determined by chemical titration NO + OBrO → NO 2 + BrO (1) with quantitative measurement of the NO 2 product by UV absorption. The cross section at the peak of the C 2 A 2 (710) ← X 2 B 1 (000) transition, ∼491 nm, was determined to be (1.8 ± 0.5) × 10 -17 cm 2 molecule -1 . During these measurements another gas phase UV absorber was observed to originate from the OBrO source. The possible identity of this species and its influence on the OBrO absorption cross section determination are discussed.