Reaction dynamics of C(1<i>D</i>)+H2(<i>v</i>)→CH(<i>X</i> 2Π)+H

Abstract

The CH(X 2Π,v,J,Ω,Λ) product state distribution from the reaction C(1D)+H2(v)→CH+H was determined by laser-induced fluorescence (LIF) where the B 2Σ–X 2Π transitions were probed. Most of the available energy is released as translation. A nearly thermal rotational distribution is obtained for CH(v=0,1). Only a small fraction, 4.1×10−4, of the CH products is formed in the vibrationally excited state. A higher propensity for the production of CH in the symmetric Π(A′) Λ sublevels is evident. For studying the influence of vibrational excitation on the reaction dynamics, H2 was excited to its first vibrational state via stimulated Raman pumping (SRP). H2(v=1) increases the reaction rate and enhances the population of higher rotational states, but diminishes the Λ selectivity. The vibrational population ratio P(v=0)/P(v=1) of the CH product remains unaltered. Insertion of the C(1D) atom into the H2 bond is the major reaction mechanism, but the probability for an abstractive process seems to increase when H2(v=1) is reacting with C(1D).