A highly sensitive method for time-resolved detection of O(1D) applied to precise determination of absolute O(1D) reaction rate constants and O(3P) yields†
Abstract
We demonstrate detection, in the gas-phase, of O(1D2) at concentrations down to 107 cm−3 and develop this new method for time-resolved kinetic studies allowing both the total removal rate of O(1D2), of up to 1.5 × 106 s−1, and the fraction quenched to O(3PJ) by species X, kq/k(X), to be determined precisely from a single time profile: at 295 K we find, k(O(1D2) + N2O) = (1.43 ± 0.08) × 10−10 cm3 s−1 with kq/k(N2O) = 0.056 ± 0.009; k(O(1D2) + C2H2) = (3.1 ± 0.2) × 10−10 cm3 s−1 with kq/k(C2H2) = 0.020 ± 0.010; kq/k(H2O) < 0.003 for O(1D2) +