Atmospheric chemistry of iodine anions: elementary reactions of I−, IO−, and IO2− with ozone studied in the gas-phase at 300 K using an ion trap
Using a radio-frequency ion trap to study ion–molecule reactions under isolated conditions, we report a direct experimental determination of reaction rate constants for the sequential oxidation of iodine anions by ozone at room temperature (300 K). The results are R1: I− + O3 → IO− + O2, k1 = (7 ± 2) × 10−12 cm3 s−1; R2: IO− + O3 → IO2− + O2, k2 = (10 ± 2) × 10−9 cm3 s−1; R3: IO2− + O3 → IO3− + O2, k3 = (16 ± 2) × 10−9 cm3 s−1. More oxidized forms such as IO4− and IO5− were not observed. Additionally, we performed quantum chemical calculations to elucidate the energetics of these oxidation reactions.