Collisionally induced rotational energy transfer within the A2Δ state of CH

Abstract

Time resolution of dispersed laser-induced fluorescence of the A²Δ–X²Π origin band of CH has been used to measure rates of rotational energy transfer within the A²Δ state. The dominant collision partner is helium at ambient temperature. Transfers with |ΔN|= 1 have the highest probability. The measured rates are adequately represented by the energy corrected sudden scaling law (ECS-P model). The rate constant for total transfer out of the lower rotational levels (ca. 0.9 × 10^–10 cm³ s^–1) is close to gas-kinetic.