Rotational and vibrational energy transfer in CH(A 2Δ)

Abstract

Rate constants have been obtained for rotational and vibrational energy transfer within the A ²Δ state of CH by collisions with Ar and N₂. By using laser photolysis of CHBr₃ as the source of CH(A), it was possible to produce a wide range of rotational and vibrational levels (N⩽ 25, v⩽ 2). The rate constants for rotational relaxation are comparable to gas kinetic rates (k < 2.5 × 10^–10 cm³ molecule^–1 s^–1) and decrease with increasing rotational quantum number. The efficiency of vibrational relaxation is ca. 10 times less than that of rotational relaxation (k < 6.5 × 10^–12 cm³ molecule^–1 s^–1).