The puzzle of high lifetime and low stabilization of HO3˙: rationalization and prediction.

One of the most important puzzles in atmospheric chemistry is the long-lifetime of HO₃˙ in spite of its low-stabilization energy. In the present work, we have estimated the lifetime of HO₃˙ using classical dynamics simulations by coupling an available neural-network analytical potential energy surface with a chemical dynamics program. The simulation results clearly indicate that at room temperature, the lifetime of HO₃˙ can exceed 1 μs under collision-free conditions. In fact, at 200 K, the lifetime of HO₃˙ can enter the millisecond timescale. This suggests that HO₃˙ is indeed a stable enough intermediate that can affect the outcomes of crucial atmospheric processes.