A highly intense state-selected CH radical beam and its application to the CHÂ +Â O2 reaction

A highly intense pulsed supersonic CH(X2Π) radical beam source was developed by use of the C(1D) + H2 reaction. CH radicals were state-selected by an electrostatic hexapole field. The focusing curves for the single state-selected CH were measured for the first time by a saturated laser-induced fluorescence (LIF) spectroscopy for the R-branch in A2Δ3/2 ← X2Π1/2 transition. The maximum CH flux intensity in the lowest ∣J, F, M〉 state, ∣1/2, 2, 1/2〉 was measured by LIF to be 3.2 × 1012 rad cm−2 s−1 at the focusing point of 150 cm downstream from the nozzle.