Hyperfine structure and lifetime of the C 2Σ+, v=0 state of CH

Abstract

From a laser induced fluorescence (LIF) experiment on a molecular beam of CH, we have obtained the b and c hyperfine constants, the γ and γ_D spin‐rotation constants as well as accurate values for the rotational constants B, D, and H for the C ²Σ⁺, v=0 state. From measurements of the linewidths, that are partially caused by predissociation, and by comparing relative line intensities, we determined different lifetimes for upper (F₁) and lower (F₂) ρ‐doublet states of the C ²Σ⁺ state. For the F₁ states we find a constant lifetime of 3.7±1.0 ns, that is independent of N, while for the F₂ states we observed an increase in lifetime for higher N up to 8.0±1.5 ns for N=11.