Time-resolved study of hydrogen atoms in the H2–O2 system under conditions close to criticality
Abstract
A time-resolved study has been performed at conditions close to criticality in the H2–O2 system. Reaction was initiated by the exciplex laser flash photolysis of O2 at 193.3 nm. H was monitored using time-resolved resonance fluorescence and showed an approximately biexponential time dependence. Near the explosion limit, the long-time behaviour is dominated by the competition between the branching and terminating H + O2 channels. Rate coefficients for these channels were inferred from this time dependence over the ranges 800 ⩽T/K ⩽ 850 and 100 ⩽P/Torr ⩽ 243.