Hot-atom chemiluminescence: a beam study of the reactions C(3P)+H2→CH(A 2Δ, B 2Σ−, C 2Σ+)+H

A beam of carbon atoms at energies 10–180 eV was generated by charge transfer of C+ ions with CCl4 gas. Chemiluminescent reactions of the fast C atoms with H2 were observed by the spectrally resolved emissions in the CH(A 2Δ–X 2Π, B 2Σ−–X 2Π and C 2Σ+–X 2Π) band systems. The relative cross-sections for CH production in the A, B and C states are different: A and B state formation both appear at the thermodynamic threshold, but the A state is observed up to ∼23 eVCM and B only to ∼8.5 eVCM. C-state formation is observed between 7 and 20 eVCM. High-resolution A–X and B–X spectra at low and medium energy indicate that the rotational product excitation increases with collision energy.