A quasi-static method for measuring the deactivation rate constants of O2(a1Δg) in gas phase by IR radiation decay

A quasi-static method is developed for measuring the deactivation rate constants of O2(a1Δg) in gas phase by monitoring its IR radiation decay via a flow-stop technique. This method has taken into account the energy-pooling reaction of O2(a1Δ) and thus suits fairly high O2(a1Δ) concentration without identifying its absolute value, leading to simpler operation and higher signal/noise ratio. Utilizing this method, the O2(a1Δ) deactivation rate by D2O is for the first time measured to be 2.10 ± 0.18 × 10−18 cm3 s−1, while those for O2( X 3 Σ g - ), H2O, H2 and D2 are found to agree well with the data in literature.